Tektronix 491 Maintenance Manual Download Page 46

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and D1016, is configured as a voltage doubler. The

circuit

p r o v i d e s a p p r o x i m a t e l y - 3 7 0 0 v o l t s f o r t h e c a t h o d e o f

the CRT and is the reference voltage for the half-wave rectifier

D1020, which develops an additional -150 volts (approxi-

mately) for the CRT grid to cathode bias.

A sample of the high voltage is taken from the voltage

divider circuit and applied to an error sensing and amplifier

circuit, Q1000, Q1001 and Q1002. This circuit controls the

current through the high voltage oscillator to regulate the

high voltage output.

Q1003,

with the primary windings of T1010 plus the dis-

tributed circuit capacitance, comprise the high voltage oscil-

lator. Q1002, in shunt with the emitter-base winding of the

oscillator, regulates the oscillator current.

Q1000

compares a sample of the high voltage with the

-10 volt regulated supply. The error voltage is amplified

through the complementary amplifier and regulator Q1001

and Q1002.

The emitter of Q1002 or output of the regulator is con-

nected through R1009 to the +10 volt supply, This provides

the initial forward bias to the base of Q1003. Positive feed-

back from the collector winding to the base-emitter wind-
ing causes the circuit to oscillate. Frequency of oscillation

is dependent on transformer winding capacitance, including

reflected reactance of the secondary windings, Frequency

of oscillation is approximately 50 kHz.

The voltages supplied by the secondary windings of T1010

are: +175 V for the +150 volt regulator circuit in the low
voltage power supply; -3700 V for the CRT cathode; 6.3

VAC for the CRT heater, and grid bias voltage for the

CRT. All of these voltages are regulated by the regulator

circuit. The amplitude of the oscillator output signal, or

the transformer primary voltage, is dependent on drive

voltage to the base of Q1003. The DC base voltage of

Q1003 is set by the base voltage of Q1002.

The HV Adjust R1001 sets the forward bias for the am-

p l i f i e r Q 1 0 0 0 . T h i s s e t s t h e c u r r e n t t h r o u g h Q 1 0 0 1 a n d

Q1002. Far example: A decrease in the high voltage load
(current demand decreases) will decrease the forward bias

of Q1000 and a positive-going signal is applied to the base

of Q1001. This decreases the DC voltage at the base of

Q1003. The feedback therefore decreases the oscillator out-
put and the output high voltage will remain constant, Ripple

reduction is a factor of the amplifier gain.

R1032 (Intensity Range) and R1033 (INTENSITY level con-

trol) provide a range from 0 to approximately 100 volts

bias for the CRT to vary the CRT beam current. FOCUS

R1028 and ASTIGMATISM R1038 controls provide a variable

positive (with respect to the cathode) control voltage to the

focusing anode and astigmatism grid. These two controls

are normally adjusted in sequence for optimum beam focus

over the CRT graticule area.

Trace Rotation.

The Trace Rotation control provides

means to align the horizontal trace on the CRT with the

graticule lines. The Trace Rotation adjustment R1035 varies

the magnetic field about the coil around the CRT. It will

rotate the horizontal beam approxi3°.

Blanking Circuit.

Blanking in this CRT is dependent on

the voltage difference between the deflection blanking plates.

When the voltage difference between the plates is significant,

few electrons strike the phosphor and the CRT is blanked,

The voltage on one defection blanking plate (pin 9) is

fixed at approxi80 volts by the voltage divider

R1040-R1042. The voltage on the other plate (pin 7) is de-

pendent on the output level of the operational amplifier
Q1080 and Q1081.

The quiescent level (no-trace period) of Q1080 collector

is about +10 V and the electron stream from the cathode of

the CRT is deflected to the side because of the voltage dif-

ference between the plates, No beam or trace is visible on

the screen. During sweep time, a negative unblinking pulse

is applied to the base of Q1081 This raises the operational

amplifier DC output level to the voltage level on the other

blanking plate so the electron stream can now poss through

to the CRT screen, The beam or trace is now visible.

I n t e n s i f i e r C i r c u i t .

Signal intensification or hose line

suppression provides increased contrast between spectrum

signals and the baseline of the display.

The video signal is applied through diodes D1050 and

D1051 to one side of a comparator amplifier Q1050 and

Q1051. The input video signal is compared against a DC

level set by the INTENSIFIER control R1013 and the resultant

differential output is applied across the base-emitter junction

of Q1070.

The positive-going input video from the detector circuit

produces an output voltage from the comparator amplifier

which will decrease the forward bias of Q1070. This produces

a negative-going voltage at the collector of Q1070. This

voltage is applied through the CONTRAST control R1075 to

the input of the operational amplifier Q1081 ond Q1080. A

negative-going signal from the intensifier circuit adds to the

unblinking voltage signal and modulates the CRT blanking

plates so that the CRT beam is intensity modulated (Z axis

modulation),

Diode D1073 provides a reference voltage to ground for

the collector of Q1070. With no signal input, the collector

p o t e n t i a l o f Q 1 0 7 0 i s a p p r o x i m a t e l y + 1 0 v o l t s , T h e I N -

TENSIFIER control sets the quiescent current through the

intensifier circuit, which sets the DC level at which intensifica-

tion begins, CONTRAST control R1075 adjusts the amplitude

of the moduating signal to the unblinking circuit. This deter-

mines the contrast between the suppressed baseline and the

video signal.

Low Voltage Power Supply

The low voltage power supply in the Type 491 (see Power

Supply schematic diagram) consists of three inter-related sup-

plies that operate together as a system. This system delivers

r e g u l a t e d a n d f i l t e r e d v o l t a g e s o f - 1 0 , + 1 0 a n d + 1 5 0

volts, A common power transformer T900 supplies the input

power to each of the supplies. The input circuit to the power

transformer primary can be altered so the Type 491 will

operate through a voltage range from 90 VAC to 136 VAC.
A second plug-in connector switches the transformer primary

winding from 115 V nominal to 230 V nominal line voltage

by connecting the windings in series for 230 VAC operation

or in parallel for 115 VAC operation, The Operating section

of the manual describes connector switch positions for each

voltage range. Unless otherwise specified, the Type 491 is

shipped with T900 connected for 115 VAC input.

3 - 1 4

Summary of Contents for 491

Page 1: ...H N I C A L M A N U A L OPERATOR S ORGANIZATIONAL DIRECT SUPPORT GENERAL SUPPORT AND DEPOT MAINTENANCE MANUAL INCLUDING REPAIR PARTS SPECTRUM ANALYZER TEKTRONIX INC MODEL 491 6625 494 2937 H E A D Q U A R T E R S D E P A R T M E N T O F T H E A R M Y DECEMBER 1969 ...

Page 2: ...bserve safety precautions Learn the areas containing high voltage in each piece of equipment Be careful not to contact high voltage or 115 volt ac input connections when installing or operating this equipment Before working inside the equipment turn power off and ground points of high potential before touching them ...

Page 3: ...B C 6625 494 2937 CONTENTS Characteristics Operating Instructions Circuit Description Maintenance Performance Check Calibration Abbreviations and Symbols Electrical Parts List Mechanical Parts List Information Mechanical Parts List Diagrams Mechanical Parts List Illustrations Accessories BASIC ISSUE ITEMS LIST MAINTENANCE ALLOCATION CHART REPAIR PARTS LIST Abbreviations and symbols used in this ma...

Page 4: ...i i Fig 1 1 The Type 491 Spectrum Analyzer ...

Page 5: ...F I CENTER FREQ control and FINE RF CENTER FREQ controls centered TABLE 1 1 Minimum CW Sensitivity S N 2N Band and Supplemental Scale RF CENTER FREQUENCY 1 kHz RESOLUTION 100 kHz RESOLUTION Information A 1 10 275 MHz 100 dBm 80 dBm B 2 275 900 MHz 110 dBm 90 dBm 3 800 2000 MHz 105 dBm 85 dBm C 4 1 5 4 0 GHz 110 dBm 90 dBm 5 3 8 8 2 GHz 100 dBm 80 dBm 6 8 0 2 4 Ghz 95 dBm 75 dBm 7 12 4 18 0 GHz 90 ...

Page 6: ...acy 0 1 dB dB IF GAIN Control Range 50 d B Display Flatness with IF CENTER 3 dB maximum amplitude variations from Band 1 10 MHz to 275 MHz 50 MHz dis FREQ at 000 10 MHz to 12 4 GHz persion 6 dB maximum amplitude variations from Bands 2 through 8 275 MHz to 40 GHz 12 4 GHz to 40 GHz 100 MHz dispersion Incidental FM IF 200 H z Typically 100 Hz Up to 400 Hz if power line frequency drops to 48 Hz IF L...

Page 7: ...VAC MED 104 to 126 VAC HIGH 112 to 1 3 6 V A C Line voltage ranges provide regulated DC 230 volt range LOW 180 to 220 VAC voltages when line contains less than 2 MED 208 to 252 VAC total harmonic distortion HIGH 224 to 272 VAC Line Frequency 48 to 440 Hz Input Power 55 watts maximum CATHODE RAY TUBE Information T4910 7 1 P7 Approximately 3 75 kV internal 8 divisions vertical by 10 divisions horizo...

Page 8: ... axis Meets National Safe Transient type of test when correctly packaged One hour vibra tion slightly in excess of 1 G 30 inch 18 inches for R491 drop on any corner edge or flat surface Supplemental Information Automatic resetting thermal cutout protects instrument from overheating Altitude referred to sea level Operating temperature capabilities decline 10 C per 1000 feet altitude above sea level...

Page 9: ...e function of the front and rear panel controls and connectors power supply connection and a procedure for first time operation to intro duce the operator to the operational functions of the controls The remainder af the section then describes operation tech nique with some measurement applications and signal interpretations Front Cover and Handle The front cover furnished with the Type 491 provid...

Page 10: ...g it into the correct position Select a range which is centered about the average line voltage to be applied to the instrument See Fig 2 3 4 Re install the cover Make certain the cover fits firmly against the rear panel so the line fuses are seated in their sockets and tighten the two cap screws 5 Before applying power to the instrument check that the indicating tabs on the switch bars are protrud...

Page 11: ... without de gradation in performance spurious responses and signal compression Usually in units of dBm Minimum usable dispersion The narrowest dispersion ob tainable for meaningful analysis Defined as ten times the incidental frequency modulation when limited by incidental frequency modulation in units of Hz Phase Lock The frequency synchronization of the local oscillator with a stable reference f...

Page 12: ...trace SCALE ILLUM Controls graticule light level FOCUS Adjusts spot size for optimum display definition ASTIGMATISM Used in conjunction with the FOCUS con trol to adjust spot shape and obtain optimum display de finition INTENSIFIER Controls the relative brightness between the displayed signal and the trace baseline POSITION TWO 2 controls that position the CRT beam in the vertical and horizontal p...

Page 13: ...nputs and bands A 10 275 MHz B 270 2000 MHz and C 1 5 40 GHz FINE RF CENTER FREQ A 10 turn control to provide a fine adjustment of the RF local oscillator frequency Especially useful in tuning the oscillator to a phase lock condition with the reference frequency MIXER PEAKING A two position control that optimizes the conversion of the first local oscillator for bands B and C Does not affect band A...

Page 14: ...ols TIME DIV 10ms VARIABLE CAL SLOPE LEVEL FREE RUN SOURCE I N T Analyzer DISPERSION RANGE DISPERSION COUPLED RESOLUTION IF ATTENUATOR dB IF CENTER FREQ FINE VIDEO FILTER VERTICAL DISPLAY G A I N RF CENTER FREQUENCY FINE RF CENTER FREQ INT REF FREQ MIXER PEAKING Controls MHz DIV Controls coupled together and in the 10 MHz div position All switches OFF position Centered 000 Midrange O F F LIN C C W...

Page 15: ...NGE switch to kHz DIV then decrease the DISPERSION TO 20 kHz div keeping the signal centered on screen with the IF CENTER FREQ con trol Slowly rotate the FINE RF CENTER FREQ control Note the positive action of the phase lock circuit before lock is lost Return the signal to its locked mode by adjusting the FINE RF CENTER FREQ control 19 Uncouple the RESOLUTION and turn the control clockwise Note th...

Page 16: ...ppress the baseline at slow sweep rates in preparation for display photography See Fig 2 6 Signal Application The application of any RF signal to the Type 491 is deter mined by its frequency and level Signals between 10 MHz and 275 MHz are applied to the Band A BNC connector Frequencies from 275 MHz to 2 GHz are applied to the band B N type connector and band C covers the remaining fre quency rang...

Page 17: ...s stronger than 15 dBm applied to the input or mixer will damage or burn out the mixer diodes Mismatches between the signal source and the RF INPUT connectors may be caused by signal source output imped ance long coaxial cables etc These mismatches will ad versely affect display flatness When optimum flatness is desired and signal strength is adequate a 50 Ω attenuator pad of approximately 6 to 10...

Page 18: ...wever can be varied from approximately 100 kHz to less than 1 kHz by uncoupling the RESOLUTION control and changing it as an independent function of the DISPERSION selector Dispersion accuracy is a function of the IF CENTER FREQ control position and the DISPERSION RANGE switch set ting See Characteristics section The dispersion accuracy far the kHz div selections is greater than the MHz div select...

Page 19: ...e MHz DIV posi tion adjust the IF CENTER FREQ CAL for minimum signal shift as the DISPERSION is switched through the MHz 10 MHz 2 MHz positions e Return the DISPERSION to the 5 MHz div position Position the signal to the graticule center with the Horizontal POSITION control If the signal is more than 1 division from the sweep center it will be necessary to adjust the internal Sweep Center adjustme...

Page 20: ...osition Fig 2 12 illustrates the effect of each display mode or each position of the VERTICAL DISPLAY switch The LOG position increases the dynamic range of the dis play by attenuating large amplitude signals more than small amplitude signals This produces a display which approxi mates a logarithmic response curve The circuit is basically a compression circuit and is most effective when there are ...

Page 21: ...n time between the modu lation pulses See Fig 2 13 Triggering the Sweep For most applications the trigger LEVEL control is switched to the FREE RUN position and the sweep repetition rate is a function of the TIME DIV selector settings In some applications particularly at 0 dispersion or when slaving the Type 491 to a recorder it may be desirable or necessary to trigger the display The Type 491 may...

Page 22: ...hen operating on the high frequency scales with narrow dispersion or fine adjustment to establish a phase lock condition Fig 2 15 Adjusting FINE RF CENTER FREQ control for phase lock operation When searching a frequency band set the MIXER PEAK ING control to SEARCH position and tune slowly through the band with the RF CENTER FREQUENCY control This ensures that signals of sufficient power within a ...

Page 23: ...ase lock amplifier Part of the input signal is coupled through and displayed when the LOCK CHECK button is pushed This permits the operator to re establish a particular lock point that may be lost because of oscillator drift or other reasons The opera tor adjusts the FINE RF CENTER FREQ control while observ ing the display until the signal is again at a particular lock point the point where the ba...

Page 24: ...2 16 Fig 2 17 Control set up chart ...

Page 25: ...some basic spectrum analyzer displays Fig 2 19 Formation of a spectrum F is the fundamental or carrier frequency F1 and F2 are the modulating frequencies Spectrum of Amplitude Modulation When a single frequency CW signal is amplitude modu lated by a single frequency two additional frequencies will be generated the carrier plus the two side bands See Fig 2 18 The amplitude of either sideband with r...

Page 26: ...es a theoretical voltage spectrum of a square pulse pulse modulated oscillator The main lobe and the side lobes are shown as groups of spectral lines extend ing above and below the baseline The number of these side lobes for a truly rectangular pulse approaches infinity since the number of harmonics in a square pulse approaches an infinite quantity Any two adjacent side lobes are separated an the ...

Page 27: ...se is twice the IF away from the true or dial calibrated response Har monics of the local oscillator fundamental frequency also convert incoming signals to the IF response For example the second harmonic of 900 MHz 1800 MHz will mix with 1600 MHz and 2000 MHz These response are identified and read as follows 1 Tune the RF Center Frequency across a dispersion win dow and observe the signal movement...

Page 28: ...moves 25 MHz for an RF CENTER FREQUENCY change of 50 MHz the next lower scale should be used 6 The rate at which the signal moves across the disper sion window as the RF CENTER FREQUENCY is tuned also aids in identifying which scale to use and with practice the correlation of the signal rate of movement and the dial scale becomes fairly easy Spurious responses due to intermodulation are the most d...

Page 29: ...he dial reading The frequency of an applied signal is measured as follows 1 Check the calibration of the IF CENTER FREQ CAL adjustment as described under Front Panel adjustments 2 Set both IF CENTER FREQ controls and the FINE RF CENTER FREQ control to their midrange 000 position 3 Set the DISPERSION RANGE switch to kHz DIV and the DISPERSION selector to 500 kHz div 4 Tune the RF CENTER FREQUENCY s...

Page 30: ... power supply noise and ripple vibration or other random factors Fig 2 24 shows the random frequency modulation characteristics of a klystron series of photographs to show the frequency drift as a function of time Temperature compensation can be recomputed by this process since the amount and direction of the drift may be graphically indicated by photographs Amplitude Modulation Modulating frequen...

Page 31: ... a cOS 2 curve and identifies the signal as frequency modulation Frequency Deviation Measurement There is no clear relationship between spectral width and deviation because in theory the FM spectrum approaches infinity In practice however the spectral level falls quite rapidly as shown in Fig 2 26B Accurate deviation measurements can be made if the modulating frequency and the modulation index whe...

Page 32: ...e VERTICAL DISPLAY switch to accen tuate these minima points Usually LOG position 5 Calculate the dispersion of either the main lobe or a side lobe as directed under measuring frequency difference The pulse width is equal to the reciprocal of the main lobe frequency width or the reciprocal of the side lobe frequency width See Fig 2 27 Repetition Rate The pulse repetition rate is measured when the ...

Page 33: ...urces line external and internal The signal from the sweep generator is applied to both the sweeper oscillator through the variable dispersion circuit and to the horizontal amplifier circuit for the horizontal sweep on the CRT The horizontal CRT beam movement and the frequency scan in the 2nd mixer are therefore synchro nized This provides the calibrated dispersion and a linear display of the freq...

Page 34: ...Fig 3 1 Function block diagram of the Type 491 3 2 ...

Page 35: ... This reduces oscillator drift and incidental frequency modulation permit ting narrow dispersion settings for signal analysis The phase detector samples the instantaneous RF voltage generated by the tunable local oscillator at a rate determined by the reference frequency The sample voltages are then intergrated and applied to a comparator which generates a corrective voltage to feed back to the lo...

Page 36: ... trigger Q1121 into avalanche and the resulting collector current sweeps out the stored charge of diodes D1134 and D1139 When the charge has dissipated the diodes generate a fast recovery step This recovery step is differentiated and coupled through trans mission line transformer T1140 T1150 and T1160 to the phase detector as a series of equal amplitude positive and negative strobe pulses The phas...

Page 37: ...as the Band selector is switched between bands The FINE RF CENTER FREQ control must be centered for this adjustment Sweeper Circuit This circuit see Fig 3 5 provides a swept frequency centered at 275 MHz to the wide band mixer amplifier The swept frequency amplitude is constant and the dispersion can be varied from about O Hz to 100 MHz A positive going sawtooth voltage from the sweep genera tor c...

Page 38: ...dispersion the oscillator sweeps from 225 MHz to 325 MHz Output signal from the oscillator is tapped across the partial winding of L314 and capacitively coupled to trans formers T330 and T331 The transformers step the voltage up about 2 1 and converts the single ended signal to a bal anced push pull drive signal for the output amplifier Q340 and Q350 Fig 3 6 is a simplified drawing of the transfor...

Page 39: ...ends of two transmission lines The transmission lines are 1 8 wavelength long at the center frequency 275 MHz One line is open ended and appears capacitive the other line is shorted and appears inductive at the center frequency As the input frequency to the dis criminator increases the transmission line input impedance nears the characteristics of a wavelength line The shorted transmission line in...

Page 40: ... Freq Range adjust ment R251 and CAL R250 calibrate the frequency range of the IF CENTER FREQ control over the IF center frequency Wide Band 1 50 250 MHz Amplifier and Second Mixer The wide band amplifier contains band pass filter two amplification 3 8 an input 150 250 MHz stages and a mixer ampilifer with its output tuned to 75 MHz Gain through the amplifier is approximately 20 dB The wide band r...

Page 41: ...the overload characteristics of the amplifier Out The 75 MHz IF and the output from o crystal controlled put of the 5 MHz IF signal is applied through an insulated 70 MHz oscillator Q440 are applied to the mixer amplifier connector J470 to the input of the variable resolution am Q450 The collector output circuit of Q450 is T454 which plifier Fig 3 8 Crystal variable resolution filter Fig 3 9 Cryst...

Page 42: ...Fig 3 10 Block diagram of the video detector and vertical amplifier 3 1 0 ...

Page 43: ...ad which is primarily the parallel resonant circuit therefore bandwidth becomes a function of the Q for the resonant circuit The Q of the output load circuit for the crystal is varied by changing the bias of diodes D506 which changes the shunt loading across the parallel tuned circuit As the forward bias of D506 is increased the Q of the parallel resonant circuit decreases and the response char ac...

Page 44: ...a paraphase output am plifier The operational amplifier consists of the grounded base amplifier Q660 driving the emitter follower Q670 and the inverter amplifier Q680 Output signal from the collector of Q680 is fed back to the input of the amplifier through R672 Vert Gain adjustment in series with R671 to the emitter of Q660 Gain of the amplifier is a function of the ratio Rf Rin Rf is controlled ...

Page 45: ...51 to its forward bias state At this point the gating multivibrator is flipped to its pretriggered state The emitter of Q752 now steps up to approximately 9 volts When the emitter voltage of Q752 steps up Q771 is turned on hard This applies forward bias to the disconnect diode and timing current plus extra base current is now supplied by Q771 The Miller circuit now starts to run down and will cont...

Page 46: ...oltage difference between the deflection blanking plates When the voltage difference between the plates is significant few electrons strike the phosphor and the CRT is blanked The voltage on one defection blanking plate pin 9 is fixed at approximately 80 volts by the voltage divider R1040 R1042 The voltage on the other plate pin 7 is de pendent on the output level of the operational amplifier Q108...

Page 47: ... However any error in the output is reduced by a factor equal to the loop gain of the regulator circuit 10 Volt Supply and Regulator Error sensing far the 10 volt supply is accomplished by the amplifier Q930 A sample of the 10volt supply is applied from the voltage divider R934 R935 in series with the regulator Q920 to the base of Q930 This voltage sample is compared with the 10 volt emitter refer...

Page 48: ......

Page 49: ...d dust with a dry soft paint brush Remove the loosened dirt by vacuum and or dry low pressure compressed air high veloc ity air can damage certain components Hardened dirt and grease may be removed with a cotton tipped swab or a soft cloth dampened with water and a mild detergent solu tion such as Kelite or Spray White Abrasive cleaners should not be used C A U T I O N Do not permit water to get i...

Page 50: ...n the troubleshooting procedure in this section Performance Checks and Recalibration To insure accurate measurements the instrument per formance should be checked after each 500 hours of opera tion or every six months if the instrument is used intermittent ly The calibration procedure is helpful both in the isola tion of major troubles in the instument and in locating minor troubles which are not ...

Page 51: ...ng The widest color stripe identifies the first color of the code Power supply voltages can be identified by three color stripes and the background White background indi cates a positive supply and a tan background is used to indicate a negative supply Table 4 2 shows the wiring color code for the power supply voltages used in the Type 491 The color coding helps trace a wire from one point in the ...

Page 52: ...oard assembly are shown in Figs 4 3 through 4 9 Make certain the pin connectors are perpendicular with the pins when connecting to prevent bending or spreading the pin connectors If the connectors are grasped near the wire end by a pair of needle nose pliers their removal or installation is relatively easy Removal of the High Voltage Compartment Components in the high voltage compartment can be re...

Page 53: ...Fig 4 4 Power Supply Circuit board assembly with wiring color code 4 5 ...

Page 54: ...Fig 4 5 Horizontal Display circuit board assembly showing color code to pin connectors 4 6 ...

Page 55: ...Fig 4 6 IF Control board assembly Wiring color code to pin connector 4 7 ...

Page 56: ...ck or implode The CRT may be stored by placing the tube face down on a smooth surface with a protective cover or soft mat under the faceplace to prevent scratches The removal and replacement procedure for the CRT tube and shield assembly is as follows 1 Unsolder the trace rotation leads 4 8 Fig 4 8 Connector assembly board for the RF oscillator assembly and wiring color code to the pin connector 2...

Page 57: ... Calibration section Removing the TIME DIV Switch Assembly The horizontal display board may either be removed before removing the switch assembly or it can remain mounted If the board is not removed disconnect the necessary pin connectors to the board so the assembly can be removed 1 Remove the VARIABLE and TIME DIV control knobs plus the mounting nuts and washers 2 Disconnect the lead from capaci...

Page 58: ...Grasp the nylon rocker arm linkage at the switch SW365 end and lift the linkage off the switch lever 3 Remove the two mounting screws that hold the switch assembly mounting bracket to the side frame 4 Slide the switch assembly back and lift the assembly out 5 Loosen the set screws for the drive gears on bath the switch shaft and the drive shaft Loosen the set screw through the mounting bracket cas...

Page 59: ...15 1 Remove the B band Mixer assembly by removing the front panel mounting nut and washer for the assembly Slide the assembly to the rear then lift out and position the assem bly so that it is clear of the cover 2 Loosen the large barrel nut on the C band receptacle then disconnect the right angle Sealectro connector from the diplexer Remove the receptacle assembly A number of turns are required t...

Page 60: ...nto the box be sure to install the wires on the pin connector before replacing the box assembly 8 Remount the assembly using the reverse of the removal procedure Do not force the assembly into place Check the wiring and connectors to avoid wire pinching or strain on the connectors Removing the Line Voltage Selector Use a pin extractor Model 107 R 1001 manufactured by Winchester Electronics Div of ...

Page 61: ...replace the mixer diode See Fig 4 18B 3 Band C Mixer Diodes a Coaxial Mixer Unscrew the base of the coaxial mixer Fig 4 18C Replace the diode and re assemble the mixer b Waveguide Mixers Unscrew the cap over diode and replace the diode See Fig 4 18D Oscillator Tube Replacement N O T E A complete oscillator assembly and its sub parts are listed in the Mechanical Parts section Replac ing components ...

Page 62: ...heck its operation 2 Band C oscillator tube replacement V42 The procedure to replace this tube is described and illustrated in Fig 4 20A and 4 20B Component Replacement The physical size and shape of the replaced component may affect the performance of the circuit therefore it is best to duplicate the original component as much as possible Parts orientation and lead dress should also duplicate tho...

Page 63: ...dy This frees the leads for individual unsoldering 2 Grip the lead with needle nose pliers Apply the tip of the soldering iron to the connection at the back of the board then pull gently to remove the lead 3 When the lead comes out of the board it should leave a clean hole If not the hole should be cleaned by reheating the solder and placing a sharp object such as a wooden toothpick or enameled wi...

Page 64: ...Fig 4 20A Tube subassembly removal procedure 4 16 ...

Page 65: ...Fig 4 20B Tube subassembly installation procedure 4 17 ...

Page 66: ... switch do not let solder flow around and beyond the rivet on the switch terminal Exces sive solder can destroy the spring tension of the contact T R O U B L E S H O O T I N G Attempt to isolate trouble to one circuit through opera tional and visual checks Verify that the apparent trouble is actually a malfunction within the Type 491 and not improper controls setting or malfunctioning associated e...

Page 67: ...often a con venient way to detect defective transistors Before substi tuting a transistor it is recommended that circuit conditions be checked to be certain that an exact replacement will not be damaged If a transistor is removed from its socket make certain it is replaced in the same socket in the same position Some transistors can be inserted incorrectly into their socket Fig 4 21 shows the corr...

Page 68: ...Fig 4 22 Power supply board assembly with component call out 4 2 0 ...

Page 69: ...Fig 4 23 Vertical Amplifier and Blanking board assembly with component call out 4 21 ...

Page 70: ...Fig 4 24 IF control board assembly with component call out 4 22 ...

Page 71: ...Fig 4 24 IF control board assembly with component call out 4 23 ...

Page 72: ...Fig 4 25 Horizontal display board with component call out 4 24 ...

Page 73: ...Fig 4 25 Horizontal display board with component call out 4 25 ...

Page 74: ...Fig 4 26 Phase lock board with component call out 4 26 ...

Page 75: ...ttenuators 1 dB and 10 dB steps accuracy 1 5 dB to 90 dB below 1 GHz Hewlett Packard Type 355C and 355D Step Attenuators 7 Harmonic Generator Tektronix Calibration Fixture 067 0594 00 8 200 MHz Trap Tektronix Calibration Fixture 067 0595 00 9 Two 2 GR to BNC male adapters Tektronix Part No 017 0064 00 10 Clip lead adapter BNC Tektronix Part No 013 0076 00 11 Termination 50 Ω BNC Tektronix Part No ...

Page 76: ...lly 1 ms CAL FREE RUN I N T MHz DIV 10 MHz div All switches OFF Midrange 000 Midrange O F F LIN RF Band Selector FINE RF CENTER FREQ MIXER PEAKING Phase Lock Controls INT REF FREQ A Centered 5 turns from either extreme Search O F F 1 Trace Alignment a Requirement Horizontal trace alignment is not criti cal and is usually set to the operator s requirement If mis alignment is excessive approximately...

Page 77: ... from the Type 491 TRIG IN connector 8 Check Line Triggering a Requirement Sweep will trigger on LINE with the LEVEL control centered and the SLOPE switch in either posi tion b Set the SOURCE switch to LINE position c Check for a triggered sweep with the LEVEL control centered and the SLOPE switch in either the or posi tions 9 Check Sweep Timing a Requirement Sweep timing accuracy must be within 3...

Page 78: ... DISPERSION control is switched between 100 kHz div and 1 kHz div positions j Check There should be less than 2 major division signal shift as the DISPERSION control is rotated down to the 1 kHz div position The IF CENTER FREQ CAL adjust ment should not be against the stop k Return the DISPERSION RANGE to MHz position and the DISPERSION COUPLED RESOLUTION control to 10 MHz div position 12 Check th...

Page 79: ...mize inter ference of the converted signals tunable signals c Set the DISPERSION RANGE to kHz DIV position and the DISPERSION to 50 kHz div Uncouple the RESOLU TION and turn the control fully clockwise Set the TIME DW to 1 s d Adjust the GAIN control for an 8 division display amplitude e Check the bandwidth of the 200 MHz signal at the 6 dB amplitude point by switching in 6 dB attenuation with the...

Page 80: ...ough signal Must equal or exceed 2 5 MHz Note the dial read ing when the control is 2 5 MHz from center This reading will be referred to later in the procedure c Center the IF CENTER FREQ controls and change the DISPERSION to 50 kHz div Apply 10 ns and 10 µs 100 kHz markers to the Type 491 RF INPUT d Check the range of the IF CENTER FREQ FINE control Must equal or exceed 50 kHz either side of cent...

Page 81: ...ence oscillator by aligning the 1st marker with the 1st graticule line and noting the displacement of the 9th marker from the 9th graticule line The INT REF FREQ control must be turned to the initial on position to make this frequency check There should be no noticeable difference in the postion of the marker with the position noted in step e h Set the DISPERSION RANGE to kHz DIV and the DIS PERSI...

Page 82: ...e accuracy of the IF ATTENUTOR dB selectors as follows 1 Switch the Type 491 1 dB attenuator siwtch to ON and switch out 1 dB of attenuation through the units step attenua tor 2 Check the display amplitude Must equal 6 div 0 7 minor division 1 dB dB 3 Switch the IF ATTENUATOR switch to OFF position then check the remaining IF ATTENUATOR switch steps as directed in Table 5 4a Spectrum Step Signal A...

Page 83: ...sis ground d Check Signal amplitude at the TO RECORDER con nector should equal or exceed 24 mV 4 mV div 22 Check Incidental Frequency Modulation a Requirement With the DISPERSION RANGE at kHz DIV the IF incidental FM should not exceed 200 Hz The incidental FM of the local oscillator plus the IF with phase lock must not exceed 300 Hz N O T E Signal source must supply a very stable signal to accurat...

Page 84: ...Ad just MIXER PEAKING for maximum signal amplitude before measuring flatness h Remove the signal from band B INPUT and apply the output from signal generators that cover scales 4 through 6 frequency range to band B Coaxial Mixer i Check response flatness through the frequency range of the Coaxial Mixer Maximum amplitude variation over 100 MHx dispersion window must not exceed 3 dB Adjust MIXER PEA...

Page 85: ...be centered i Check the dial accuracy as listed in Table 5 7 Must equal or exceed 2 MHz 1 of the dial reading j As the dial accuracy is checked depress the LOCK CHECK button and check for phase lock beats Check for a phase lock operation at the center and extreme frequency position for each scale Dial accuracy need only be checked for scales 1 2 and 4 The remaining scales are harmonic settings of ...

Page 86: ...EQ control 5 Slowly adjust the FINE RF CENTER FREQ control until the LO loses the lock The signal may shift off screen Re establish phase lock by adjusting the FINE RF CENTER FREQ control to return the signal on screen 6 Slowly adjust the INT REF FREQ VARIABLE control Note the signal shift across the dispersion window as the reference oscillator frequency is changed Range of the control is approxi...

Page 87: ...plitude of Spurious Signals from Internal Sources Requirement With the DISPERSION RANGE at kHz DIV for band A spurious signals must not exceed 2 times noise amplitude With DISPERSION RANGE at MHz DIV for bands B and C spurious signals should be down more than 40 dB with 100 kHz resolution b Connect a 50 W termination on band A RF INPUT connector and switch the band selector to band A c Set the DIS...

Page 88: ......

Page 89: ...t probes 2 Time Mark Generator Marker outputs 5 s to 1 µs and frequency outputs of 20 MHz 50 MHz 100 MHz and 200 MHz accuracy 0 001 Tektronix Type 184 Time Mark Generator 3 Audio Signal Generator Frequency range 10 Hz to 1 MHz variable output amplitude to at least 10 volts peak to peak accuracy 3 General Radio Model 1310A or Hewlett Packard Model 241A 4 VHF Signal Generator Frequency range 10 MHz ...

Page 90: ...Fig 6 1 Test equipment recommended for calibration of the Type 491 6 2 ...

Page 91: ...Fig 6 2 Test equipment recommended to measure the dial accuracy receiver sensitivity and response flatness 6 3 ...

Page 92: ...mpedance 50 Ω Suggested equipment Hewlett Packard 612A UHF signal generator 450 MHz t o 1230 MHz Hewlett Packard 8614A UHF signal generator 800 MHz to 2400 MHz Hewlett Packard 8616A UHF signal generator 1800 MHz to 4500 MHz Polarad 1107 Microwave signal generator 3 8 GHz to 8 2 GHz Polarad 1108 Microwave signal generator 6 95 GHz to 11 0 GHz Hewlett Packard 15 5 GHz Hewlett Packard 21 0 GHz Hewlet...

Page 93: ...LINE trigger on and SLOPE positions 12 13 14 15 16 17 18 19 20 21 22 23 Adjust Sweep Length Page 6 17 Adjust Sweep Length R759 for 7 5 volt peak to peak sawtooth at pin S of the Horizontal Display board Adjust Sweep Calibration and Sweep Gain Page 6 17 Adjust Sweep Gain R813 for 10 5 division sweep length Adjust Sweep Cal R787 for calibrated sweep Use 1 ms timing markers applied to pin H of Vertic...

Page 94: ...ck Accuracy of IF ATTENUATOR selectors Page 6 31 Apply a signal within the frequency range of one band from a Signal Generator with a calibrated vari able attenuator output to an RF INPUT connector of the Type 491 Check the accuracy of each IF ATTENUATOR dB selector against the calibrated attenuator on the Signal Generator Accuracy must equal or exceed 0 1 dB dB of attenuation 31 Check Attenuation...

Page 95: ...ance will be obtained if each adjustment is set to the exact setting even if the Check is with in the allowable tolerance The following pro cedure uses the equipment listed under Equipment Required Preliminary Procedure Remove the instrument from the container connect the autotransformer if used to a suitable power source then connect the Type 491 power cord to the autotransformer output or direct...

Page 96: ... All switches in off VIDEO FILTER VERTICAL DISPLAY G A I N POWER MIXER PEAKING FINE RF CENTER FREQ PHASE LOCK Controls INT REF FREQ Band Selector Steps 1 through 6 OFF L I N Midrange O N SEARCH Centered O N B POWER SELECTOR Proper voltage settings for power source used See Operating Instructions Test Oscilloscope Time Cm 1 ms Volts Cm 005 Input Coupling AC 1 Adjust 10 volt supply o N O T E The 10 ...

Page 97: ...s Connect the lead of the battery to pin AQ on the power supply board Connect the lead of the battery to pin Al a Equipment setup is given in step 1 b Connect the voltmeter between pin L of the Vertical Amplifier and Blanking circuit board and chassis ground see Fig 6 5 Check the 10 volt supply Must read between 9 7 and 10 3 volts 10 V 3 c Connect the voltmeter between pin M of the Vertical Amplif...

Page 98: ...the current may exceed 800 mA and blow the high voltage fuse e Adjust the Intensity Range R1032 for a current read ing of 750 mA f Turn the POWER switch to OFF remove the meter leads and replace the high voltage fuse Check that the fuse is a 1A fast blow Turn the POWER switch to ON then readjust the INTENSITY and POSITION controls for a cen tered trace of nominal brightness 5 Check Power Supply Vo...

Page 99: ...ulation Amplitude 1 0 V 9 9 to 1 0 1 V 1 m V 1 0 V 9 7 to 10 3 V 2 m V 150 V 145 5 to 154 5 V 5 m V c The following calibration steps do not require a line voltage control unit Return the Line Voltage Selector to the operating range for the existing power source voltage The Type 491 may be connected directly to the power source for the remainder of the calibration 6 Adjust Trace a Test equipment b...

Page 100: ... of nominal brightness Adjusted for optimum display definition As desired Adjusted for a horizontally centered sweep on the grati cule baseline 2 mS CAL FREE RUN INT MHz DIV 5 MHz div All switches in off position Midrange 000 OFF LIN CCW ON Fig 6 9 Test equipment setup for adjusting Vertical Amplifier Gain MIXER PEAKING SEARCH FINE RF CENTER FREQ Centered PHASE LOCK Controls OFF or EXT REF FREQ IN...

Page 101: ...rough a 1 test probe to pin H of the Vertical Amplifier circuit board d Adjust the Vertical Amplifier Gain R672 Fig 6 10 for a signal amplitude on the Type 491 of 5 major divisions 8 Check Range of Vertical Position Control a Test equipment setup is given in step 7 b With a 0 5 volt signal applied to pin H of the Vertical Amplifier board adjust the Vertical POSITION control through its range c Che...

Page 102: ...WER O N MIXER PEAKING SEARCH FINE RF CENTER FREQ Centered PHASE LOCK Controls I N T R E F F R E Q O N Test Oscilloscope Time Cm 1 ms Volts Cm 2 Input Coupling DC Trigger Adjust for free running sweep 9 Adjust Trigger Level Centering o a Equipment setup is shown in Fig 6 11 b Apply the output signal of the Audio Signal Generator to pin H of the Vertical Amplifier circuit board Set the Audio Signal ...

Page 103: ...gnal Generator frequency to 20 Hz and adjust the output for 0 2 volts Monitor the output ampli tude with the test oscilloscope d Change the Type 491 Triggering SOURCE switch to EXT position and the TIME DIV switch to 1 s position e Check external triggering Must trigger with a 20 Hz 0 2 volt signal applied with the SLOPE switch in either the or positions f Increase the Audio Signal Generator frequ...

Page 104: ... SOURCE selector to LINE posi switch to the ON position tion e Check line triggering with the SLOPE switch in both the and positions Display must trigger on the cor c Turn the POWER switch OFF then connect a 10 test rect slope probe and a BNC to clip lead adapter between pin H of f Remove the 10 probe and clip lead adapter Return the Vertical Amplifier circuit board and pin 17 of the power the TIM...

Page 105: ... All switches in off position Midrange 000 O F F L I N Midrange O N MIXER PEAKING FINE RF CENTER FREQ PHASE LOCK Controls INT REF FREQ Test Time Cm Volts Cm Input Coupling Trigger SEARCH Centered OFF Oscilloscope 1 ms 2 DC lnt Triggered display 12 Adjust Sweep Length o a Equiment setup is given in Fig 6 14 b Connect the probe from the test oscilloscope to pin S of the Horizontal Amplifier circuit ...

Page 106: ... line c Check timing accuracy 3 at each position of the TIME DIV selector Marker input and Type 491 display for each position is listed in Table 6 3 15 Check VARIABLE Control Range a Equipment setup is given in step 14 b Apply 5 ms markers to pin H of the Vertical Amplifier circuit board assembly Set the Type 491 TIME DIV selector to 1 ms and adjust the Triggering LEVEL control for a stable displa...

Page 107: ... DIV to 20 ms c Adjust the GAIN control for a displayed IF signal ampli tude of 6 divisions Tune the RF CENTER FREQUENCY control for minimum converted signal interference d Establish zero volt reference level on the test oscillo scope by connecting the probe to chassis ground on the Type 491 then connect the probe to pin P of the square pin con nector for the honeycomb assembly See Fig 6 17 Fig 6 ...

Page 108: ...range O N S E A R C H FINE RF CENTER FREQ Centered PHASE LOCK Controls INT REF FREQ O F F Test Oscilloscope Time Cm 1 ms Volts Cm 5 Input Coupling A C 21 Adjust MHz DIV Dispersion and o Linearity N O T E Dispersion accuracy is a measure of the frequency dispersion error within 8 divisions of a 10 division display It is measured by positioning the 1st fre quency marker on the 1st graticule line the...

Page 109: ...ve been installed or components have been changed and linearity cannot be obtained by other means a Equipment setup is given in Fig 6 19 b Apply 1 µs and 10 ns markers from the Time Mark Generator Type 184 through a 20 dB attenuator to band B RF INPUT connector Set the VERTICAL DISPLAY switch to LOG position c Adjust the Type 491 GAIN control for a display ampli tude of approximately 6 divisions S...

Page 110: ...d in Table 6 4 The Horizontal POSITION central or the IF CENTER FREQ control may be used to align the prime markers to the graticule divisions As the DISPERSION is decreased the RESOLUTION control should remain in the coupled posi tion d Check the range of the IF CENTER FREQ control plus the dispersion accuracy and linearity over this range in the 5 2 1 5 and 2 MHz positions of the DISPERSION sele...

Page 111: ...couple the RES OLUTION control and turn fully clockwise All switches in off position Midrange 000 O F F L I N POWER O N MIXER PEAKING SEARCH FINE RF CENTER FREQ Centered PHASE LOCK Controls INT REF FREQ OFF Test Oscilloscope Time Cm 1 ms Volts Cm 0 5 Input Coupling AC Trigger L I N E 23 Adjust IF Amplifier Response and o Resolution Bandwidth a Equipment setup is shown in Fig 6 23 N O T E Resolutio...

Page 112: ...ply the 200 MHz signal from the Time Mark Generator through a 20 dB attenuator and adapter to the Waveguide Mixer adapter Switch the band selector to c 2 Apply 200 MHz signal below 50 dBm from an ac curate signal generator through a 50 Ω termination or attenu ator and a P6041 or P6040 probe cable adapter to sub miniature connector J100 on the wide band pass filter of the honeycomb assembly c Turn ...

Page 113: ... 6 27 for optimum display symmetry on the test oscilloscope See Fig 6 25 Adjust C504 for the slope of the response and C508 for symmetry Turn the RESOLUTION selector counterclockwise one step from fully clockwise position Adjust C601 C604 C607 and C610 for optimum display symmetry and amplitude Fig 6 28 location of resolution filter adjustments and 100 kHz Resolution Cal R543 j Check display symme...

Page 114: ...INE kHz DIV 500 kHz div All switches in off postion Midrange 000 O F F L I N O F F VIDEO FILTER G A I N Midrange POWER O N MIXER PEAKING SEARCH FINE RF CENTER FREQ Centered PHASE LOCK Controls INT REF FREQ O F F 24 a Adjust kHz DIV Dispersion Equipment setup is shown in Fig 6 29 N O T E An alternate setup to check kHz div dispersion is as follows Replace the Coaxial Mixer for band C with the Waveg...

Page 115: ...io signal source Apply the RF signal to the RF Input and the audio frequency to the Mod Freq 1 Input of the Harmonic Modulator Connect the Modu Harm Out connector through a 20 dB attenuator to the RF INPUT connector of the Type 491 This will provide an IF feedthrough signal modulated by the audio frequency for fre quency markers 25 a b Check Dispersion of the kHz div Selector Positions Test equipm...

Page 116: ... IF center frequency Check the accuracy with the IF CENTER FREQ control centered then rotate the control to the dial reading noted in step c for 2 5 MHz from center and check the dispersion accuracy Decrease the sweep speed as the dispersion is decreased and increase resolution by uncoupling the RESOLUTION selector Turn the control counterclockwise to optimize mark er definition Switch the VERTICA...

Page 117: ...ne 2 ms CAL Triggered LINE kHz DIV 50 kHz div All switches in off position Midrange 000 OFF LIN Midrange ON MIXER PEAKING SEARCH FINE RF CENTER FREQ Centered PHASE LOCK Controls INT REF FREQ O N Test Oscilloscope Time Cm 5 µs Volts Cm 05 Input Coupling AC Triggering Int Phase Lock Circuit 26 Adjust Avalanche Voltage o a Equipment setup is given in Fig 6 32 b Connect the Vertical Input of the test ...

Page 118: ... up is given in step 26 b Apply the output from the 1 MHz MARKERS OUT signal through a 10 attenuator to J120 on the honeycomb assembly as follows Connect a GR to Sealectro adapter such as a P6040 probe cable a GR to BNC adapter and a 20 dB attenuator see Fig 6 32 between the 1 MHz MARK ERS OUT connector and J120 Disconnect the Sealectro connector from J120 c Set the DISPERSION to 100 kHz Div and p...

Page 119: ... J120 and J109 28 Adjust Band C Balance then Band A o and B Balance a Equipment setup is as given for step 26 b Turn the INT REF FREQ control ON and the band selector to band C c Set the FINE RF CENTER FREQ control to its midrange position d Push the LOCK CHECK button and adjust the Band C Bal R1140 for a centered trace e Switch the band selector to B or A f Push the LOCK CHECK button and adjust t...

Page 120: ...SITION Horizontal and Adjusted for a horizon Vertical tally centered sweep on the graticule baseline T I M E D I V 10 ms VARIABLE CAL TRIGGER SLOPE LEVEL SOURCE DISPERSION RANGE D I S P E R S I O N C O U P L E D R E S O L U T I O N IF ATTENUATOR dB IF CENTER FREQ VIDEO FILTER VERTICAL DISPLAY G A I N POWER MIXER PEAKING FINE RF CENTER FREQ PHASE LOCK Controls I N T R E F F R E Q F R E E R U N I N ...

Page 121: ...attenuation through the Units Step Attenuator 2 Check the display amplitude Must equal 6 divisions 0 7 minor divisions 3 Switch the 1 dB ATTENUATOR switch to the OFF posi tion then check the remaining IF ATTENUATOR dB steps as directed in Table 6 6a T A B L E 6 6 a Spectrum Analyzer Limit 1 dB dB Signal Amplitude I F A T T E N U A T O R Switch on Units T e n s 1 dB 11 20 5 93 to 6 07 div 2 dB 10 2...

Page 122: ...d portion of the signal should measure between 3 5 and 4 5 major divisions Fig 6 37 Typical display showing incidental frequency modulation 33 a b Check Signal Amplitude at the TO RECORDER Connector Equipment setup is given in step 29 Set the VERTICAL DISPLAY switch to the LIN position adjust the Signal Generator output and the Type 491 GAIN control for a signal amplitude of 6 divisions c Connect ...

Page 123: ...R FREQ control to keep the signal centered on screen e Adjust the GAIN control for an 8 division signal amplitude f Check the display frequency modulation see Fig 6 37 Must not exceed 1 minor division 200 Hz g Change the DISPERSION to 100 kHz div and move the IF feedthrough signal off screen with the IF CENTER FRE QUENCY control Center the tunable 200 MHz signal on screen with the RF CENTER FREQUE...

Page 124: ...ling AC tally centered sweep on Trigger Int the graticule baseline 20 ms CAL FREE RUN I N T M H z D I V 5 M H z D I V 20 dB switch on Midrange 000 O F F L I N Midrange O N Manual 36 Adjust the Wide Band Amplifier o Response and Check the System Response Flatness N O T E The Type 491 response flatness and sensitivity is dependent on the combined response of the wide band amplifier the bandpass filt...

Page 125: ...he applied signal frequency Adjust the MIXER PEAKING for maximum signal amplitude Adjust the GAIN plus the variable attenuator of the signal generator for a signal amplitude of 6 divisions i Calibrate the output amplitude of the RF signal from the signal generator j Tune the signal generator frequency through a 100 MHz band and check the response flatness of the Type 491 Signal amplitude should no...

Page 126: ... band A RF INPUT and apply a signal within the frequency range of band B to RF INPUT B Set the band selector to B and set the DISPERSION to 10 MHz div T A B L E 6 8 6 Check display flatness as per Table 6 8 3 dB maxi mum amplitude variation over 100 MHz window 50 MHz from RF center frequency Maximum signal amplitude with the MIXER PEAKING control before measuring flat ness 7 Remove the signal from...

Page 127: ...ATOR dB SCALE ILLUM As desired IF CENTER FREQ POSITION Horizontal Adjusted for a horizont VIDEO FILTER and Vertical ally centered sweep on the graticule baseline VERTICAL DISPLAY T I M E D I V 5 ms GAIN VARIABLE CAL POWER TRIGGER M I X E R P E A K I N G SLOPE FINE RF CENTER FREQ LEVEL FREE RUN PHASE LOCK Controls SOURCE I N T I N T R E F F R E Q MHz DIV 2 F u l l y C W 20 Midrange 000 O F F L I N ...

Page 128: ...cal oscillator feedthrough signal must not exceed 2 n o i s e amplitude If a spur appears at approximately 37 5 MHz readjust the mixer balance h Move the 50 Ω termination to band B RF INPUT con nector switch the band selector to B and set the DISPER SION to 10 MHz div i Adjust the GAIN control for 1 division of noise then tune through the band B frequency range checking for spuri ous signals whose...

Page 129: ...itch to the appropriate band c Set the DISPERSION to 500 kHz div and the RESOLU TION control for a resolution bandwidth of 100 kHz fully clockwise d Adjust the GAIN control for an average noise ampli tude of one division Center the IF CENTER FREQ and FINE RF CENTER FREQ controls e Tune the signal on screen with the RF CENTER FRE QUENCY control Reduce the signal amplitude with the signal generator ...

Page 130: ...LOCK CHECK button and check for phase lock beats Check for a phase lock display at the center and extreme frequency posi tions for each scale Dial accuracy need only be checked for scales 1 2 and 4 The other scales are harmonic settings of these fundamental ranges k CHECK Phase lock operation with an external refer ence frequency as follows 1 Apply a 1 V peak to peak 1 MHz signal from the Con stan...

Page 131: ...eak and repeat the check with the increased signal ampli tude at 5 MHz and 1 MHz 38B Alternate Procedure to Check Dial Accur acy Oscillator Mixer Operation and Ef fectiveness of Local Oscillator Phase Lock a Equipment setup is shown in Fig 6 46 b Apply 100 MHz 10 ns markers from the marker output of the time mark generator through the harmonic generator the 200 MHz trap and the 20 dB attenuator to...

Page 132: ...XER PEAKING control to optimize signal amplitude Note the spectral display of the harmonic genera tor signals Tune the RF CENTER FREQUENCY through the band checking for dead spots which could be caused by either local oscillator failure or mixer malfunction The MIXER PEAKING must be peaked at all check points e Check Local oscillator phase lock operation as follows 1 Turn the INT REF FREQ control ...

Page 133: ...e is no need to check dial calibration for the upper scales of band C because they are multiples of scale 4 h Apply 10 MHz 1 µs marker signals and harmonics to the band A RF INPUT Switch the band selector to A Set the DISPERSION to 1 MHz div i Check the dial accuracy oscillator and mixer perform ance and LO phase lock operation through band A Check by using the same procedure that was used to chec...

Page 134: ... MHz The BAND A LOCAL OSCILLATOR dial tape should read 635 8 MHz on scale 2 If the tape does not read within this range the coupling between the two oscillators must be reset Adjust the coupling as follows a Loosen the two set screws through the flexible cou pling to the band B rear oscillator drive shaft b Set the tape to read exactly 635 c Hold the front shaft at 635 on the dial and manually tun...

Page 135: ... 48 9 Set the frequency meter to 210 MHz Tune the dial to 10 MHz and adjust the A band inductance adjustment Fig 6 49 to tune the oscillator freuency to 210 MHz drive shaft coupling and tuning adjustments 10 Set the frequency meter to 475 MHz Tune the dial tape to 275 and adjust the A band capacitance adjustment Fig 6 49 to tune the oscillator frequency to 475 MHz 11 Repeat steps 9 and 10 until bo...

Page 136: ...from the access hole turn the POWER switch ON and return the oscillator frequency to 470 MHz 6 Again check the dial reading If necessary again turn off the POWER switch and repeat step 4 until the dial reads 270 when the oscillator frequency is 470 MHz 7 Set the frequency meter to 1100 MHz and tune the dial to 900 8 Adjust the band B capacitance adjustment see Fig 6 48 to tune the oscillator frequ...

Page 137: ...rew to No 2 port and rotate probe assembly for maximum power input Do not rotate the probe 180 from the preset position If power output exceed 100 mW decrease the coupling by pulling the probe as sembly out Tighten the set screws i Loosen the set screws 1 in Fig 6 50 and position the plate choke for a frequency of 4 2 GHz Force the lead screw against the bearing and tighten the set screws j Loosen...

Page 138: ......

Page 139: ...ead steel height or high hexagonal hex head brass hex head steel hex socket brass hex socket steel inside diameter incandescent int lg met mtg hdw OD OHB OHS PHB PHS plstc PMC poly prec PT PTM RHB RHS SE SN or S N S w TC THB thk THS tub var w WW internal length or long metal mounting hardware outside diameter oval head brass oval head steel pan head brass pan head steel plastic paper metal cased p...

Page 140: ...oved after this serial number 000 0000 00 Asterisk preceding Tektronix Part Number indicates manufactured by or for Tektronix Inc or reworked or checked components Use 000 0000 00 Part number indicated is direct replacement o Screwdriver adjustment Control adjustment or connector 6 B ...

Page 141: ...0 281 0616 00 281 0105 00 281 0616 00 281 0105 00 281 0101 00 281 0099 00 281 0101 00 281 0648 00 281 0101 00 281 0099 00 281 0101 00 281 0635 00 281 0523 00 283 0599 00 BO101 00 B1 19999 0 001 F B120000 0 001 UF 0 8 8 5 pF Var 0 8 8 5 pF Var 8010100 8119999 47 pF B1 20000 47 pF 10pF 0 8 8 5 pF Var 10pF 0 B 8 5 pF Var 10pF 0 8 8 5 PF Var 10pF 0 8 8 5 pF Var 0 001 KF 6 8 pF 0 8 8 5 pF Var 6 8 pF 0 ...

Page 142: ...0610 00 283 0039 00 283 0003 00 283 0003 00 283 0050 00 283 0050 00 281 0503 00 283 0050 00 281 0105 00 283 0039 00 281 0635 00 283 0039 00 0 001 pF 180 pF 0 001 pF 1000 pF XB040000 6 8 pF 9 35 pF Var 1000 pF 0 001 pF 180 pF 1000 pF 18pF 68 pF 100 pF 0 001 KF 1000 pF 68 pF 68 pF 68 pF 68 pF 0 01 LF 0 1 pF 0 01 pF 0 01 pF 0 01 LF 0 001 pF 0 01 pF 0 01 pF 10 LF 0 05 pF 0 001 pF 0 001 pF 10pF 1000 pF...

Page 143: ...03 00 283 0039 00 283 0001 00 281 0599 00 283 0065 01 0 01 pF 0 001 pF 0 005 pF 1 pF 0 001 pF 100V 500 v 500 v 200 v 100V 5 281 0564 00 281 0105 00 283 0065 01 283 0065 01 283 0065 01 24 pF 0 8 8 5 pF Var 0 001 LF 0 001 LF 0 001 pF 500 v 100V 100V 100V 5 281 0645 00 281 0105 00 283 0065 01 283 0001 00 283 0001 00 O 25 pF 5 8 2 pF 0 8 8 5 pF Var 0 001 pF 0 005 pF 0 005 JF 500 v 100V 500 v 500 v 281...

Page 144: ... 283 0027 00 281 0541 00 283 007940 283 0079 00 285JJ736 00 283 0079 00 283 0027 00 283 0027 00 283 0027 00 283 0027 00 283 0027 00 0 001 bF 0 01 ILF 0 01 pF 0 01 LF 0 01 LF 0 01 pF 33 pF 8 90 pF Vor 678 pF 15pF 90 pF Var 678 PF 15pF 8 90 pF Var 678 pF 15pF 8 90 pF Var 678 pF 33 pF 0 01 LF 0 001 pF 0 001 pF 0 01 pF 0 01 AF 0 01 pF 0 01 AF 33 pF 33 pF 0 01 47 pF 0 1 IAF XB130000 0 01 LF 0 01 pF 1 p...

Page 145: ...5 07034XI 283 0008 00 285 0572 00 283 0120 00 28 N20 00 0 01 AF 1000pF O F O B1 AF 10PF 0 01 0 001 pF 0 01 4 7 pF 0 01 0 001 LF 0 01 pF 0 02 pF 0 1 pF loox20x20pF 0 001 pF 0 001 801 O1 I3 8059999 100pF 1000PF 0 02 pF 4500 pF 10 LF 22 pF 0 02 LF 1000 AF 0 01 pF 25 LF 150 LF 0 03 1 LF 1 jLF 0 01 pF 0 02 F 0 01 LF 0 02 pF 1 pF 0 1 pF 0 1 ILF 0 1 pF 0 1 pF 0 1 IAF 0 015 AF 0 015 F Cer 250 v Cer 500V 1...

Page 146: ...83 0127 00 283 0127 00 283 0127 00 283 0065 00 283 0065 00 283 0078 00 283 0065 00 283 0078 00 283 0003 00 283 0065 00 283 0059 00 283 0065 00 283 0003 00 BO101 00 B050000 BO101 00 B050000 0 01 pF 1 pF 0 01 pF 0 01 pF 0 01 ILF 1 5 pF 0 02 LF 0 01 pF 100 pF 0 01 LF 0 01 LF 240 pF 0 001 LF 68 pF 0 01 AF 82 pF 0 1 pF 0 001 pF 4 7 pF 4 7 pF 2 5 pF 0 001 pF 4 7 pF 2 5 pF 2 5 pF 2 5 pF 2 5 pF 2 5 pF 2 5...

Page 147: ...00 B089999 B090000 Germanium Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Zener Zener Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Germanium Germanium Germanium Germanium Germanium Germanium Germanium Zener Zener Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silir rl Tunnel 1 N82A matche...

Page 148: ...tifier Bridge Silicon Zoner 1 N3194 1N3194 1 N935A 0 4 W 9 1 V 57 0 TC Replaceable by 1 N4152 Replaceable by 1N4152 D952 D953 D964 D967 152 0066 00 152 0066 00 152 0123 00 1 52 0185 00 1 52 0185 00 Silicon Silicon Zoner Silicon SiIican Replaceable by 1 N647 7701 5X Varo 7701 5X Varo Replaceable by 1 N647 Replaceable by 1 N4152 Replaceable by 1 N4152 D101 O D1014 D1016 D102O D105O D1051 1 52 0107 0...

Page 149: ...0 131 0372 00 J72 J73 J75 J80 131 0372 00 J94 131 4H72 00 JltM 131 03724 J1 W 131 037240 J120 131 0372 00 J147 131 0372 00 J1 131 0372 00 Piltor 8010100 8059999 Low Pass 275 V AC Low Pass 275 V AC Furnished as a unit with Oscillator 119 O1O6OOI Furnished as a unit w th Diplexer 1 19 01 Furnished os a unit with Resktive T Network Furnished as a unit with Mixer 119 W4 001 Connoctars BNC female Coaxi...

Page 150: ...283 00 1 08 0388 00 1 08 0385 00 1 08 0390 00 1 08 0387 00 1 08 0389 00 1 08 0386 00 1 08 0389 00 1 08 0437 00 1 08 0394 00 1 08 0380 00 1 08 0377 00 1 08 0382 00 1 08 0379 00 1 08 0381 00 1 08 0378 00 1 08 0381 00 1 08 0371 00 1 08 0370 00 1 08 0369 00 1 08 0401 00 1 0843369 00 1 08 0370 00 1 o 0371 oo Coaxial Coaxial Coaxial Coaxial Coaxial Coaxial Coaxial Coaxial Coaxial 1 contact female Coaxia...

Page 151: ...367 00 108 O36B OO 1 fj8 fj3 oo 108 0368 00 I 08 0368 00 1 08 0368 00 108 0368 OQ BO101 00 B039999 56 nH B040000 55 nH 54 66 nH Var Care 276 0506 00 234 286 nH Var Core 276 0506 00 54 66 nH Var Core 276 0506 00 0 09 l XBO101 12 0 09 YH Core Ferramic Suppressor 1 1 pH 1 1 NH Core Ferramic Suppressor 1 1 pH 1 1 pH 45 nH 27 nH 55 nH 55 nH 180 220 nH Var Core 276 0506 00 1 1 pH Core Ferramic Supressor...

Page 152: ... Silicon Silicon BO1O1OO B039999 Silicon B040000 Silicon BO101 00 B039999 Silicon 8040000 Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon 5ilicon Silicon Silicon Silicon Silicon Silicon Silico...

Page 153: ...21 2N3906 Replaceable by MPS 6521 Replaceable by MPS 6521 Q950 Q951 Q952 Q960 151 014B0 151 o192 151 0188 00 1514192 151 0192 00 Silicon Silican Silicon Silicon Silicon Q961 Q1OOO Replaceable by MPS 6521 2N3906 Replaceable by 2N3053 Selected from 2N3055 Replaceable by MPS 6521 151 0192 00 151 0188 00 151 0136 00 151 0140 00 151 0192 00 Silicon Silicon Silicon Silicon Silicon Q1OO1 Q1OO2 Q1OO3 Q105...

Page 154: ...cted nominal value Selected nominal value Selected nominal value Selected nominal value R16 R16 RI 7 y4 w ye w 1 4 w y w ye w y w 3W G y j w 3W 3W 1 4 w y4 w y4 w w w 1 4 w 1 4 w y4 w Ww Ww Ww 5 R17 R18 R18 R20 R21 B1 20000 BO101 00 B1 20000 XB1 20000 XB1 20000 20a B119999 100 2 100 2 24 Q 51 Cl 5 j R40 R41 R42 R43 R45 4 5 k 4 5 kCt 820 Q 200 K 24 7 Q 1 y 1 5 57 1 R46 R51 R55 R66 R123 24 7 Q 56 k ...

Page 155: ...3214347 00 321 0368 00 321 0205 00 321 0233 00 311 0633 00 311 0644 00 323 0348 00 321 0385 00 321 0164 00 311 0590 00 322 0481 00 311 0580 00 321 0423 00 321 0143 00 91OQ 5 6 Q 910 2 4 53 k 68 1 kct 5 k Var 7 5 k 11 8kQ 30 kQ Var 2 94 kt 2 49 k 499 c 1 k 2 499 c 249 C 49 9 c 100Q 49 9 a 30 1 c1 10Q 10C2 301 a 100Q 1 k 2 21 k 4 32 kf2 93 1 kf2 1000 7 68 k 301 ki2 30 k Var 40 2 kf 66 5 k 1 33 k 2 6...

Page 156: ...k 2kf_t Vor 8 06 kt 2 51 f l Prec 1 57 Prec 1 5 R294 R295 315 0562 00 315 0202 00 315 0102 00 315 0102 00 315 0562 00 5 6 kcr 2 k 1 k 1 kf2 5 6 kQ 57 5 57 5 5 R296 R300 R31 O R311 R316 R333 R334 315 0392 00 315 0221 00 321 0233 00 315 0431 00 315 0680 00 3 9 k 220 Q 2 61 k 430 i l 68 Q 5 5 1 5 72 5 Prec R346 R356 R361 315 0680 00 321 0395 00 315 0221 00 315 0102 00 311 0633 00 68a 127 k 220 Q 1 kQ...

Page 157: ...15 0101 00 315 0102 00 323 0365 00 315 0204 00 311 0607 00 315 0221 00 315 0161 00 315 0111 00 315 0151 00 315 0331 00 315 0511 00 315 0561 00 315 0154 00 315 0624 00 315 0624 00 315 0471 00 315 0681 00 315 0302 00 315 0471 00 315 0100 00 315 0182 00 315 0102 00 315 0103 00 315 0472 00 315 0103 00 315 0100 00 315 o1oo Oo 31 HWl 00 315 UOO 00 315 O1OO OO 315 O1O4 OO 315 0105 00 10kn 4 7 kn 150Q 15 ...

Page 158: ...0 Q 10kf BO101 00 8099999 l15kf2 B1 00000 105 k 68 1 k 20kQ Var 330 kf 470 k 100 k 1 4 Mn 412 k 200kQ Var 62 k 1 k 10kQ 10Q 3 3 kf 470 k 30 k 1 k 1 k 30 k 3 65 k 1 k 402 Q 10Q 100 ko 100 k 20kQ Var 1 kf2 100 k 10kO 140 k BO101 00 B099999 10kQ El 00000 9 76 kf 10Q 10kQ 100Q 100 2 1000 3W 1 4 w 4 w 1 4 w 4 w 7 4 w 1 4 w 1 4 w 1 4 w y w ye w w 1 4 w 1 4 w 8 w 2 w 8 w 2 w y4 w yn w 4 w 1 4 w j y y8 w ...

Page 159: ... 00 315 0332 00 315 0104 00 315 0103 00 321 0213 00 321 0239 00 321 0210 00 315 0332 00 315 0101 00 321 0207 00 321 0239 00 315 0103 00 323 0463 06 323 0425 06 323 0396 06 311 0182 00 311 0607 00 315 0101 00 llFurnish as a unit with SW786 100Q 3 3 k 100Q 100 kil Var BO1O1O4 B099999 300 k B1 00000 200 ks2 1OO I 2 49 k 100C2 loon 150 k 100GI 8 06 k 12 7 ka 5 k Var 4 7 k 1000 1 kta 10kQ 3 3 ka 100 k ...

Page 160: ...5 0103 00 321 0402 00 315 0562 00 321 0289 00 321 0289 00 311 0642 00 315 0131 00 315 0432 00 100Q 62 ko 620 Q 100 2 100Q 5 5 5 5 R795 R797 R799 R802 R803 100Q 499 ka 4 7 kfz 10s2 10 2 5 1 5 5 Prec R805 R807 R809 R811 R812 150kf 100C2 1 5 kf 30 k 1 5 k Prec Prec Ww Prec 1 y 5 1 1 1 R813 R821 R823 R824 R824 2 k Var 30 k 20 k Var BOI0100 8010111 6 8 k BO101 12 4 7 k Ww 1 R825 R825 R826 R830 R831 BO1...

Page 161: ... 0305 00 303 0305 00 3a3 0305 oo 303 0305 00 303 0275 00 3035305 00 303 0275 00 311 0647 00 30WWW0 303 0106 00 303 0335 00 3035365 00 311 o M oo 311 064 oo 311 O31O OO 3114 641 00 323 0342 00 3234X347 X 315 0154 00 315 O1O4 OO 8010100 B1 29999 B130000 BO101 00 B1 m B1 30000 Bol0100 B129999 Blm 8010100 B129999 B130000 1 62 ks 2 2 k 3 3 kc 12kn 100Q 1 47 kn oYn 2 kfl Var 8 66 kf3 loon 2 7 Q 10CA 100...

Page 162: ... 00 315 0913 00 311 0645 00 315 0101 00 315 0103 00 315 0104 00 315 0100 00 315 0473 00 315 0102 00 315 0122 00 315 0510 00 315 0101 00 315 0332 00 315 0162 00 315 0163 00 315 0101 00 317 0510 00 315 0473 00 311 0607 00 315 0333 00 308 0293 00 315 0510 00 308 0277 00 Zlllrrnished as a unit with SW1106 7 22 1 k 470 Q 3 01 k 100Q 21 k d 5kQ Var 100Q 3 92 kf 3 3 k 10CI 49 9 k 30kQ Var 10Q 22 k 100 k ...

Page 163: ...0339 00 317 0510 00 321 0340 00 321 0251 00 321 0251 00 321 0339 00 317 0510 00 321 0385 00 315 0125 00 317 0122 00 315 0155 00 317 0122 00 321 0277 00 322 0402 00 315 0103 00 315 0101 00 311 0668 00 315 0101 00 315 0103 00 322 0402 00 315 0471 00 315 0472 00 315 0203 00 315 0204 00 315 0104 00 315 0103 00 315 0682 00 315 0302 00 500 f l 10Q 51 K 1 kn Var 9 1 kn 15kQ 4 02 k 4 02 k 15 8 kf 10Q 100 ...

Page 164: ...0788 00 260 0759 01 260 0643 00 260 0820 00 260 0643 00 260 0665 00 311 0640 00 260 0664 00 Wired 262 0787 00 2600819 00 311 0182 00 260 0834 00 311 0645 00 260 0689 00 260 0677 00 Lever Toggle Toggle Toggle Toggle Toggle Toggle Rotary Rotary Rotary Toggle Rotary Lever Toggle Lever Lever Rotary Rotary Toggle BAND IF AITEN 20 dB IF ATTEN 16 dB IF ATTEN 8 dB IF ATTEN 4 dB IF AllEN 2 dB IF ATTEN 1 dB...

Page 165: ...ifilar L V Power H V Power 8010100 BOB9999 4 turns trifilar B090000 4 turns trifrlar T1140 Tl150 1 Part of C3rcuit Board 670 0504 00 Tl160 V40 V41 V42 V103O wl W14 W19 W40 W41 W42 W45 W45 W50 W50 W66 W66 z W75 W94 Who Ektren Tubes 1641 1641 Tek Spec T491 O 7 1 CRT Standard Phosphar Cable Aseomblies BO1 0100 0049999 B070000 8010100 801011 8010112 BO1O1OO B090000 BO1O1OO BOB9999 B090000 8010100 8089...

Page 166: ...4 00 1 19 0096 00 11 9 0097 00 1 19 0098 00 l 19 0099 00 1 19 0106 00 Is Selected See Mechanica I Parts List 7 26 213 6 inch 65 inch 65 8 inch 65 8 inch Crysfals 70 MHz 5 MHz 1 MHz Diplexer Multiplexer IF dual hybrid includes J45 J46 J47 Mixers 8119999 10 275 MHz Mixer Band A includes D14 and D16 10 275 MHz Mixer Band A includes D14 and D16 275 4200 MHz Mixer Band B includes D64 and J69 Mixer Coax...

Page 167: ...d or Component mounting hardware for Detail Part Parts of Detail Part mounting hardware for Parts of Detail Part mounting hardware for Assembly and or Component Mounting hardware always appears in the same indentation as the item it mounts while the detail parts are indented to the right Indented items are part of and included with the next higher indentation Mounting hardware must be purchased se...

Page 168: ...RATIONS Located behind diagrams FIG 1 FRONT FIG 2 REAR FIG 3 IF CHASSIS PHASE LOCK ASSEMBLIES FIG 4 POWER CHASSIS FIG 5 TIME DIV SWITCH OSCILLATOR ASSEMBLIES FIG 6 CRT SHIELD ASSEMBLY FIG 7 CABINET ASSEMBLY HANDLE FIG 8 491 ACCESSORIES 7 B ...

Page 169: ...oal ASTIGMATISM knob include SPRING KNOB charcaal iNTENSIFIER knob includes SPRING KNOB charcaal POSITION horizontal knob includes SPRING KNOB charcool POSITION vertical knob includes SPRING KNOB charcoal DISPERSION RANGE knob includes SCREW set 5 40 x 0 125 inch HSS KNOB red POWER OFF ON knob includes SCREW set 5 40 x 0 125 inch HSS KNOB charcoal lF CENTER FREQ fine KNOB charcoal lF CENTER FREQ f...

Page 170: ...oal GAIN knob includes SCREW set 5 40 x 0 125 inch HSS KNOB charcoal MIXER PEAKING KNOB charcoaI MIXER PEAKING knob includes SCREW set 5 40 x 0 125 inch HSS KNOB charcoal FINE RF CENTER FREQ KNOB charcoal FINE RF CENTER FREQ knob includes SCREW set 5 40 x 0 125 inch HSS KNOB charcoal PHASE LOCK NT REF FREQ KNOB charcoal PHASE LOCK INT REF FREQ knob includes SCREW set 5 40 x 0 125 inch HSS KNOB red...

Page 171: ...0 51 52 53 54 55 56 57 58 59 60 358 0301 01 358 0210 00 376 0067 00 213 0048 00 384 0419 00 3844658 00 136 0223 00 210 0940 00 BUSHING plastic BUSHING plastic 1 l 8z diameter x z inch Iang COUPLING coupling includes SCREW set 4 40 x inch HSS SHAFT extension SHAFT extension SOCKET light w hardware mounting hardware not included w socket WASHER flat 1A ID x inch OD 61 62 63 64 65 380 0110 01 1 0507 ...

Page 172: ...h BRACKET protector bar right mounting hardware not included w bracket SCREW 6 32 x 5 1 s inch PHS BRACKET protector bar left mounting hardware not included w bracket SCREW 6 32 x lA inch PHS ROD spacer mounting hardware for each not included w rod SCREW 8 32 x 5 lA inch THS FRAME rail mounting hardware for each not included w frame SCREW 10 32 x 3 8 inch 100 csk FHS SHIELDING GASKET SHIELDING GAS...

Page 173: ...ardware not included SCREW 6 32 x 5 l inch PHS w filter NUT keps 6 32x 5 4 inch CONNECTOR coaxial 1 cantact mounting hardware for each not LUG solder 3 s inch CONNECTOR terminal standoff mounting hardware for each not 6 131 0106 01 7 1 0255 00 3 1 BNC w hardware included w connector 8 131 0373 00 1 kil m 9 210 0405 00 2 1 1 included w cannector LOCKWASHER internal 2 not shown NUT hex 2 56 x 3 1 in...

Page 174: ... id inch PHS ASSEMBLY circuit board VERTICAL AMPLIFIER BLANKING assembly includes BOARD circuit PIN connector male SOCKET transistor 3 pin SOCKET transistor 3 pin mounting hardware not included w assembly SCREW sems 4 40x 5 l A inch PHB COVER plastic black 1 inches ASSEMBLY line voltage selector mounting hardware not included w body LOCKWASHER internal 6 NUT hex 6 32 x l d inch COVER line voltage ...

Page 175: ...E HARNESS high voltage CRT cable harness includes CONNECTOR single contact SOCKET CRT 14 pin SOCKET CRT 14 pin socket includes SOCKET CRT 14 pin COVER CRT socket mounting hardware not included w assembly SCREW 6 32 x 3 4 inch THS POST 0 25 diameter x 1 59 inches SCREW 6 32 x s 16 inch PHS 5 3 200 0616 00 XB1 20000 5 4 426 0319 01 5 5 426 0320 00 5 6 ili ii 5 7 17 1096 00 BO1O1OO 5 8 2144768 00 5 9...

Page 176: ...ssembly includes CONNECTOR coaxial 1 contact LUG solder SE 1 O long CAPACITOR mounting hardware for each not FASTENER plastic STRIP terminal SHIELD filter CHASSIS w hardware included w capacitor mounting hardware not included w assembly SCREW 4 40 x 3 it inch PHS CONNECTOR terminal feed thru mounting hardware for each not BUSHING plastic CONNECTOR coaxial 1 contact CAPACITOR w hardware mounting ha...

Page 177: ... pin mounting hardware for each not included w socket HOLDER socket SWITCH toggle DISPERSION RANGE mounting hardware not included w swhch WASHER key 0 255 ID x 0 375 inch OD NUT hex 1 4 40 x 5 1 inch MOUNT toroid plastic mounting hardware for each not included w mount SPACER plastic 0 188 inch long COIL mounting hardware not included w coil ROD spacer 3 8 x 5 8 inch LOCKWASHER internal 4 SCREW 4 4...

Page 178: ...171 inches J363 to J148 ASSEMBLY cable 19 6 inches J501 to J470 ASSEMBLY cable 1 lA inches Jl 88 to J401 ASSEMBLY cable 8 250 inches J188 to J401 mounting hardware not included w assembly SCREW 6 32 x 5 14 inch PHS not shown NUT hex 1 4 40 x 5 id inch not shown WASHER flat 1 4 ID x 3 8 inch OD ASSEMBLY cable 8 inches J1OO to J94 ASSEMBLY PHASE LOCK assembly includes ASSEMBLY circuit board PHASE LO...

Page 179: ...SCREW sems 4 40x 5 6 inch PHB GROMM 3 plastic 0 406 inch diameter SHIELD CABLE HARNESS phase lock ASSEMBLY cable 6 4 inches Jl 140 assembly includes CONNECTOR coaxial 1 contact w hardware ASSEMBLY cable 6 j inches Jl 150 assembly includes CONNECTOR coaxial 1 contact w hardware ASSEMBLY cable 61 4 inches Jl 160 assembly includes CONNECTOR coaxial 1 contact w hardware mounting hardware not included ...

Page 180: ...ed w chassis NUT sleeve 4 40 x 0 391 inch long 1 1 HOUSING PLATE shield bottom mounting hardware not included w plate SCREW 4 40 x 5 8 inch 100 csk FHS mounting hardware not included w assembly SCREW sheet metal 4x 3 16 inch PHS 4 2 ASSEMBLY LOW PASS FILTER assembly includes STRIP terminal not shown CAPACITOR w hardware CONNECTOR coaxial 1 contact w hardware SHIELD mounting hardwore for each not i...

Page 181: ...unting hardware for each not included w shield SCREW sheet metal 4x 3 14 inch PHS ASSEMBLY cable 9 inches Jl 140 to J42B ASSEMBLY cable 9 inches Jl 150 to J41 B ASSEMBLY cable 6 inches JI 160 to J40B ASSEMBLY cable 6 inches Jl 160 to J40B ASSEMBLY cable 41 2 inches J80 to J75 ASSEMBLY cable 5 z inches J34 to J71 ASSEMBLY cable 6 inches J20 to J18 ASSEMBLY cable 51 inches J50 to J4 ASSEMBLY cable 7...

Page 182: ...VER capacitor plastic 1 ID x 0 150 inch long CAPACITOR mounting hardware for each not included w capacitor SCREW 6 32 x 5 it inch PHS PLATE metal Iarg 8ASE plastic large ROD hex 1 4 x 9 Id inch SCREW 6 32 x 3 inch PHS CAPACITOR mounting hardware not included w capacitor SCREW 6 32 x 5 id inch PHS PLATE fiber small BASE plastic small ROD hex 1 4 x 9 6 inch SCREW 6 32 x 3 inch PHS RESISTOR mounting ...

Page 183: ...CKET transistor 3 pin mounting hardware not included w ossembly SCREW sems 4 40x 5 i inch PHB 40 670 0507 00 8 kbl 214 0506 00 136 0183 00 136 0220 00 ii ii 6 00 1 i 1 2 11 i 41 42 43 44 45 46 47 200 0709 00 210 0201 00 ili iob 1 1 1 COVER transistor LUG solder SE 4 mounting hardware not included w lug SCREW thread forming 5 32 x 3 4 inch PHS 48 49 348 0050 00 407 0307 00 10 4i7 i 1 1 GROMMET plas...

Page 184: ...ET circuit board bracket includes 6 7 210 1016 00 1 WASHER spring 0 228 ID x 0 375 inch OD 6 8 214 0788 00 1 LATCH 6 9 129 0107 00 1 POST snapslide fastener 7 0 214 0793 00 mounting hardware not included w bracket 1 PIN hinge 7 1 344 0137 00 1 CLIP retaining 72 73 74 75 76 77 78 79 80 81 82 343 0136 00 343 0089 00 348 0100 00 179 1094 00 131 0371 00 179 1095 00 131 0371 00 407 0276 00 211 0008 00 ...

Page 185: ...uded w resistor LOCKWASHER internal 3 8x 1 2 inch OD NUT hex 32 x I z inch COUPLING wire COUPLING coupling includes SCREW set 8 32 x 1 8 inch HSS CAPACITOR mounting hardware not included w capacitor HOLDER SHAFT extension SHAFT exteiwion mounting hardware not included w switch WASHER flat 8 ID x 1 1 inch OD LOCKWASHER internal 8 ID x 1 2 inch OD NUT hex s 8 32 x 6 inch ASSEMBLY circuit board HORIZ...

Page 186: ...le CA8LE HARNESS cable harness includes CONNECTOR single contact female SLEEVE mounting hardware not included w assembly SCREW sems 4 40x 5 6 inch PHS OSCILLATOR mounting hardware not included w oscillator LOCKWASHER internal 6 SCREW 6 32 x 0 375 inch Socket HS OSCILLATOR ASSEMBLY RF oscillator includes VARACTOR ASSEMBLY mounting hardware nat included w varactor SCREW set 4 40 x 1 8 inch HSS PROBE...

Page 187: ...4 inch OD COUPLING flexible coupling includes SCREW set 4 40 x 0 094 inch HSS COUPLING plastic RING coupling SPACER sprocket SPROCKEf tape SPROCKET tape mounting hardware not included w sprocket SCREW set 4 40 x 0 W4 inch HSS not shown SPOOL EXTENSION SPOOL EXTENSION mounting hardware not included w spoal extension SCREW set 4 40 x 0 094 inch HSS not shown SPOOL WASHER plastic not shown SCREW set ...

Page 188: ...SCREW 6 32 x s id inch PHS not shown 1 i i i 1 1 i i i SHIELDING GASKET SHIELDING GASKET ASSEMBLY circuit board OSCILLATOR CONNECTOR assembly includes BOARD circuit PIN connector male CABLE HARNESS cable harness includes CONNECTOR single contact female SLEEVE mounting hardware not included w assembly SCREW sems 4 40x s 6 inch PHS ASSEMBLY cable 11 inches J40A to J14 see Fig 3 IF CHASSIS PHASE LOCK...

Page 189: ...00 CLAMP plastic mounting hardware not included SCREW 6 32 x 3 4 inch FIL HS NUT square 6 32 x 1 inch 11 1 2 2 w clamp 211 0599 00 220 0444 00 12 13 HOLDER mounting hardware for each not included w holder SCREW 6 32 x 2 inches FIL HS NUT square 6 32 x 1 4 inch mounting hardware not included w assembly NUT keps 4 40x 4 inch NUT hex 4 40 x s lA x 0 562 inch long SCREW 8 32 x 5 16 inch PHS WASHER fla...

Page 190: ...FOOT plastic cap FOOT plastic mounting hardware for each not included w foot SCREW 8 32 x 1 z inches RHS WASHER flat 0 203 ID x 0 937 inch OD NUT keps 8 32x 1 l z inch FOOT plastic cap FOOT plastic mounting hardware for each not included w foot SCREW 8 32 x 1 z inches RHS WASHER flat 0 203 ID x 0 937 inch OD NUT guide hex 8 32 x 0 75 inch long THUMBSCREW 0 250 20 x 0 50x 1 125 inches long mounting...

Page 191: ...APPENDIX A BASIC ISSUE ITEMS LIST Basic issue items list will be published at a later date A 1 ...

Page 192: ......

Page 193: ...it is desired that elements ing and lubricating such as paint be defined separately they may be so listed d Adjust To rectify to the extent necessary to bring into proper operating range e Align To adjust specified variable elements of an item to bring to optimum performance f Calibrate To determine the corrections to be made in the readings of instruments or test equipment used in precise measure...

Page 194: ...educes to zero the hours or miles the equipment or component thereof has been in use l Symbols The uppercase letter placed in the appropriate column in dicates the lowest level at which that particular maintenance function is to be performed B 3 Explanation of Columns Listed below is an explanation of the columns shown in the maintenance allocation chart a Column 1 Group Number Column 1 lists grou...

Page 195: ...SECTION II B 3 ...

Page 196: ......

Page 197: ...of the item being requisitioned C 3 If DD Form 1348 is used fill in all blocks except 4 5 6 and Remarks field in accordance with AR 725 50 Complete Form as follows a In Blocks 4 5 and 6 list Manufacturer s Federal Supply Code Number followed by a colon and the Manufacturer s part number b Complete Remarks Field as follows Nomenclature of the repair part and any other identification to assist Suppl...

Page 198: ... 00 1 151 0149 00 i 151 0150 00 151 0153 00 151 0157 00 151 0173 00 151 0175 00 151 0 31 00 151 0188 00 151 0 30 00 151 0192 00 151 0199 00 151 0207 00 151 0230 00 151 1007 00 152 0075 00 152 0152 00 152 0185 00 153 05L 5 00 154 0502 00 154 0506 00 154 0510 00 158 0019 00 158 0024 00 158 0025 00 159 0022 00 159 0025 00 233 0093 00 315 0100 00 315 0101 00 315 0192 00 315 0103 00 3I5 CJ104 OO 321 02...

Page 199: ... Staff KENNETH G WICKHAM Major General United States Army The Adjutant General Distribution To be distributed in accordance with DA Form 12 37 qty rqr block No 201 operator maintenance requirements for Gun 20 mm XM163 and DA Form 12 40 qty rqr block No 168 operator and crew maintenance requirements for Gun 20 mm XM167 ...

Page 200: ......

Page 201: ...SECTION 9 DIAGRAMS MECHANICAL PARTS LIST ILLUSTRATIONS ACCESSORIES ...

Page 202: ......

Page 203: ...9 1 ...

Page 204: ...9 3 ...

Page 205: ...9 5 ...

Page 206: ...9 7 ...

Page 207: ...9 9 ...

Page 208: ...9 11 ...

Page 209: ...9 13 ...

Page 210: ...9 15 ...

Page 211: ...9 17 ...

Page 212: ...9 19 ...

Page 213: ...9 21 ...

Page 214: ...9 23 ...

Page 215: ...9 25 ...

Page 216: ...9 27 ...

Page 217: ...FIG 1 9 29 ...

Page 218: ...FIG 2 REAR 9 31 ...

Page 219: ...9 33 FIG 3 IF CHASSIS PHASE LOCK ASSEMBLIES ...

Page 220: ...FIG 4 POWER CHASSIS 9 35 ...

Page 221: ...FIG 5 TIME DIV SWITCH OSCILLATOR ASSEMBLIES 9 37 ...

Page 222: ...FIG 6 CRT SHIELD ASSEMBLY 9 39 ...

Page 223: ...FIG 7 CABINET ASSEMBLY HANDLE 9 4 1 ...

Page 224: ...FIG 8 491 STANDARD ACCESSORIES FIG 8 491 STANDARD ACCESSORIES 9 43 ...

Page 225: ......

Page 226: ...PIN 028017 000 ...

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Tektronix 491, Maintenance Manual

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