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INTERNAL

 

ADJUSTMENTS PROCEDURE

Services

 Available

Tektronix,

 Inc. provides complete instrument repair and 

adjustment at

 local Field Service Centers and at the Factory 

Service

 Center.

 Contact your local TEKTRONIX Field 

Office 

or representative for further

 information.

Test

 Equipment

For

 measurement of the power supply voltages, a 20,000 

ohms/volt

 VOM

 will give satisfactory measurements. For 

example,

 

Triplett 630 NA

 multimeter.

For 

1-MHz frequency measurement, 

a

 secondary 

frequency standard or

 other frequency source having a 

stability of at 

least 5

 parts

 on

 107 (5 parts in 108 if 

measuring

 optional 5

 MHz crystal output) is recommended 

for

 accuracy. Also recommended is

 a test oscilloscope with 

a bandwidth of at least 1 

MHz 

and a

 stable triggering circuit 

for

 

frequency-comparison

 measurement.

Procedure

NOTE

The 

performance of this

 instrument can be check at

 

any 

temperature

 within the 0° C to +50°C range.

 

Make 

any adjustment at 

a

 temperature

 between

 

+20° C 

and +30°C

 (+68° F and

 +86°F).

The

 DC

 502 can be operated either fully installed in a 

TM

 500

 Series Power

 Module or connected to a plug-in 

extender

 (TEKTRONIX Part No. 067-0645-01).

Power

 

Supply

 

Checks

 

and 

Adjustment.

 

Connect

 the 

voltmeter

 between the

 +15-volt test

 point and

 ground. 

Adjust

 R305

 for a reading of +15 volts. Then check the 

+5-volt,

 —5.2-volt, and -10-volt supplies to be within 5%.

NOTE

i

 

the instrument is operated on the plug-in extender,

 

vhe 

+5-vo!t supply may not regulate.

Time-Base

 

Frequency

 Check

 

and 

Adjustment.

 

Connect

 

the DC

 502 1-MHz

 time base reference and

 the secondary 

standard

 to the

 oscilloscope as shown. Adjust the oscillo­

scope 

to 

display several

 complete cycles.

To

 determine oscillator

 error, observe the rate of 

horizontal

 drift of

 the displayed waveform. Waveform 

moving

 to the

 right indicates

 that the time-base frequency 

is <1

 MHz; to the left, > 1 MHz. The period in

 seconds for 

the 

waveform

 to move the

 width of

 one

 cycle is equal to 

the

 frequency difference in parts in 106. For example, if 

the 

waveform

 drifts to

 the right at a rate

 of one cycle's 

width

 every

 10

 seconds, the time-base frequency is 0.1 part 

in

 106

 low. Maximum allowable frequency difference is 1 

part

 in 105

 (5 parts

 in 107 for the optional 5 MHz crystal). 

Adjust C201

 for 

no drift.

+5 V Test,

R322

—10 V Test,

 

R330

+15

 V

 Test,

R345

1-MHz test

 point

-5.2 V Test, R305, 

C201,

R330 

+15 V

 Adjust 

1-MHz

 

Clock Adjust

Summary of Contents for DC 502

Page 1: ...TEKTRONIX 550 MHz COUNTER DC 502 INSTRUCTION MANUAL Tektronix Inc P O Box 500 Beaverton Oregon 97005 Phone 644 0161 Cables Tektronix 070 1412 00 872...

Page 2: ...sure you the fastest possible service Please include thelnstrument Type Number or Part Number and Serial Number with all requests for parts or services Specifications and price change privileges reser...

Page 3: ...Option 1 Precision Time Base 1 4 Specifications 1 4 SECTION 2 THEORY OF OPERATION Input Circuits 2 1 Time Base and Control Circuit 2 2 Counter Circuits 2 3 Decode and Display Multiplex 2 4 Power Supp...

Page 4: ...DC 502...

Page 5: ...peak sensitivity and a 50 input impedance The same four measurement interval times are selectable for each input Front panel controls reset the Counter and provide Start Stop commands for the manual...

Page 6: ...play time which is continuously variable from about 0 1 second to 10 seconds or to hold a display indefinitely turn the DISPLAY TIME control 10 Pre Scale Input The DC 502 also provides a pre scaled AC...

Page 7: ...rally the best point on a waveform for triggering the counter is where the slope is steep and therefore usually free of noise On a sine wave signal for example the steepest slope occurs at the zero cr...

Page 8: ...Display time about 0 1 s to 10 s to HOLD Totalizing capacity 0 to 107 Resolution DIRECT INPUT 100 Hz at 0 01 s gate time 10 Hz at 0 1 s 1 Hz at 1 s and 0 1 Hz at 10 s Resolution 4 10 PRE SCALE INPUT 1...

Page 9: ...oing portion of the signal to ground The signal is then passed through emitter follower Q170 to U160B where it receives a final phase inversion to correspond with the input signal and becomes the deca...

Page 10: ...MHz clock signal is applied to pin 14 of U209 whose output is connected to the input of the subsequent decade Each decade is clocked with a negative going transition The DDU s are reset by a CLEAR pul...

Page 11: ...5 opens and C235 stops charging When S235 is closed and C235 charges sufficiently to bring Q238 to its firing potential T1 the display time ends and the next GATE opening sequence begins Manual Gate T...

Page 12: ...he latches to share a common set of output lines Seven Segment Decoder and Display LED s U270 is a BCD to seven decoder It accepts the BCD output of the latches then supplies current to the appropriat...

Page 13: ...ovide stable supplies of 15 volts 5 volts 5 2 volts and 10 volts The 15 volt supply whose active device is U300 provides the reference for the remaining supplies Its output is set to 15 V by adjustmen...

Page 14: ...It provides a LO output during reset or can be used as an external reset input Data Lines 1 2 4 8 provide BCD output serial by digit from the currently enabled storage register latch Other data lines...

Page 15: ...is based on MIL STD 806B in terms of positive logic Logic symbols depict the logic function performed and may differ from the manufacturer s data The following special symbols are used on the diagram...

Page 16: ...No Eff Disc Description ASSEMBLIES 670 2102 00 B010100 B039999 MAIN Circuit Board Assembly A12 670 3409 00 B040000 MAIN Circuit Board Assembly Al2 670 3410 00 MAIN Circuit Board Assembly A2 670 2103...

Page 17: ...152 CR125 J5 152 0141 02 Silicon replaceable by 1N4152 CR127 J5 152 0141 02 Silicon replaceable by 1N4152 CR128 J5 152 0141 02 Silicon replaceable by 1N4152 CR165 H5 152 0141 02 Silicon replaceable by...

Page 18: ...J1 151 0341 00 Silicon NPN replaceable by 2N3565 Q280 F2 151 0301 00 Silicon PNP replaceable by 2N3907 Q281 F1 151 0301 00 Silicon PNP replaceable by 2N3907 Q282 G2 151 0301 00 Silicon PNP replaceable...

Page 19: ...3 00 20 k 1 4 W 57 R192 Q3 315 0221 00 B010100 B059999 220 1 4 W 57 R192 Q3 315 0561 00 B060000 560 1 4 W 5 R192 Q3 315 0221 00 B010100 B049999 220 1 4 W 5 R192 Q3 315 0561 00 B050000 560 1 4 W 57 R19...

Page 20: ...327 B5 321 0260 00 R328 B5 321 0231 00 R330 C5 315 0161 00 R334 D5 321 0256 00 R335 D5 321 0308 00 R340 B4 315 0202 00 R344 D5 321 0286 00 R345 C5 321 0308 00 R350 A5 305 0101 00 B010100 R350 A5 306 0...

Page 21: ...0N U2012 E6 156 0079 00 Single 10 MHz divide by 2 5 ripple counter replaceable by SN7490N U209 E5 156 0079 00 Single 10 MHz divide by 2 5 ripple counter replaceable by SN7490N U210 D4 156 0079 00 Sing...

Page 22: ...198 00 Quad latch replaceable by MC4035P U260 M1 156 0030 00 Quad 2 input positive nand gate replaceable by SN7400N U262 K2 156 0041 00 Dual 15 MHz D type pos edge trig flip flop replaceable by SN7474...

Page 23: ...sing the RESET button 10 pre scale input Connector Lights during the active gating interval RESET Pushbutton Manual Gate Pushbutton ATTEN Pushbuttons MEASUREMENT INTERVAL Switch Two buttons select X1...

Page 24: ...39 39 Relocated on back of board SN B070000 REV MAY 1974...

Page 25: ...LOCATION GRID co See Parts List for serial number ranges I C139 R139 Relocated on back of board SN B070000 in n o N J 0 0 U260 U230 I U220 U222 S200 n o rs o 0 CC R307 added to backside of board SN B0...

Page 26: ...nected to a plug in extender TEKTRONIX Part No 067 0645 01 Power Supply Checks and Adjustment Connect the voltmeter between the 15 volt test point and ground Adjust R305 for a reading of 15 volts Then...

Page 27: ...IDER UNITS U209 U210 U211 U212 U213 U214 U215 01 SEC 1 SEC 1 SEC IO SEC CONTROL SIGNALS U230A U246D U230B U230C U230D MEAS INTER SWITCH S200 A CLEAR CLEAR RESET 10 DCU STORAGE U165A U165B U167 U169 10...

Page 28: ...OD S2 S CSAN ED W R 5 Q240 U222A Az Display Board Qiqo IUOC q CRI8IB DIRECT INPUT switch Detent Counter Time Base UI5OA CRI8IA U2OI UIGOC z F3 FT U2O9 I DISPLAY CLEAR 15 VOLTS 5 VOLTS O VOLTS measurei...

Page 29: ...lay DC 502 A4 P20TSCTION circuit board 47a F 2OV IO VOLTS USA 5 Z VOLTS REG 4 SEE PARTS UST FOR EARLIER VALUES AND SERIAL NUMBER RANGES OF PARTS MARKED WITH BLUE OUTLINE X DECI MAL 28B Point U2G2A FRO...

Page 30: ...on 1 1 366 0494 00 1 KNOB gray TRIGGER LEVEL knob includes 213 0153 00 1 SETSCREW 5 40 x 0 125 inch HSS 2 366 1031 00 1 KNOB red DISPLAY TIME knob includes 213 0153 00 1 SETSCREW 5 40 x 0 125 inch HSS...

Page 31: ...01 00 2 SCREW 2 56 x 0 25 inch PHS 29 1 CIRCUIT BOARD ASSEMBLY MAIN See Al electrical list circuit board assembly includes 30 131 0604 00 13 CONTACT electrical For repair see maint section 31 136 0252...

Page 32: ...tch S200 actuator assembly includes COVER mounting hardware not included with cover SCREW 2 56 x 0 188 inch WASHER lock internal i RING retaining BEARING front SPRING flat gold SPRING flat green SPRIN...

Page 33: ...FIG 1 EXPLODED...

Page 34: ...mediately into printed manuals Hence your manual may contain new change information on following pages A single change may affect several sections Sections of the manual are often printed at different...

Page 35: ...DC501 DC502 TEXT CORRECTION The upper limit frequency response specifications has been changed to 110 MHz Any reference to a 100 MHz should be changed to read 110 MHz C5 173...

Page 36: ...red flip flop replaceable by SN74H102 U169 156 0100 00 Single 40 MHz J K edge triggered flip flop replaceable by SN74H102 Al 670 2102 01 MAIN Circuit Board Assembly ADD 670 3300 00 DIVIDE BY 5 Circuit...

Page 37: ...Page 2 of 2 SCHEMATIC CORRECTION DC 501 DC 502 4 P A R T IA L C O U N T E R S D IS P L A Y T O 3 3 0 0 0 0 5 B O A R D M20 988 1073...

Page 38: ...SN BO70000 up ELECTRICAL PARTS LIST AND SCHEMATIC CHANGE CHANGE TO R137 311 1554 00 200 k Var ADD C121 283 0111 00 0 1 F Cer 50 V R137 and C121 are located on Diagram COUNTER TIME BASE CONTROL 5V A CR...

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