Summary of Contents for 730A

Page 1: ...www SteamPoweredRadio Com I I I I I I I I I I I 1 I 1 I 1 I S C A MODULATION MONITOR MODEL 730A J17EffL TIME AND FREQUENCY TECHNOLOGY N C...

Page 2: ...www SteamPoweredRadio Com s c A MODULATION MONITOR MODEL 730A Instrument Serial Manual Revision__A TIME FREQUENCY TECHNOLOGY INC 3000 OLCOTT STREET SANTA CLARA CA 95051 408 246 6365...

Page 3: ...www SteamPoweredRadio Com...

Page 4: ...5 Subcarrier Off Alann Connection 2 2 OPERATION 3 1 3 2 3 2 1 3 2 2 3 3 3 4 3 5 3 6 3 7 3 7 1 3 7 2 3 8 3 9 3 10 3 11 3 12 General 3 1 Controls Connectors and Indicators 3 1 Front Panel 3 1 Rear Panel...

Page 5: ...4 2 Calibration Circuits 4 3 MAINTENANCE 5 1 5 2 5 3 5 4 5 5 5 6 5 7 5 7 1 5 7 2 5 7 3 5 7 4 General 5 1 Access 5 1 Periodic Maintenance 5 1 Main Channel Modulation Accuracy Check 5 1 SCA Injection A...

Page 6: ...or an external counter The Model 730A can monitor either of two SCA carrier frequencies 41 kHz or 67 kHz selectable by front panel pushbutton switches Other SCA frequencies are available on special o...

Page 7: ...00 Carrier Frequencies 1 2 4 kHz or 6 kHz 67 kHz standard 41 kHz optional Modulation Accuracy OdB Meter Attenuator Switch Position 1 kHz 100 2 Frequency Response Composite Input 20 Hz to 6 kHz 20 Hz t...

Page 8: ...f 2 kHz SCA Modulation and Injection Level Calibrator Outputs Built in modulation and injection level calibrator for calibrating the modulation meter and the positive and negative peak flashers from t...

Page 9: ...10 mv 115 230 _ 10 VAC 50 to 400 Hz 25 watts maximum Physical and Environmental Operating Temperature Size Wei ght Accessory Equipment 66 dB 55 dB 7 high x 19 wide x 16 deep Approx 15 lbs 1 3 1 3 1 M...

Page 10: ...unit will be repaired and returned to the BUYER with transportation charges prepaid by SELLER Transportation charges for instruments found to be defective within the first thrity 30 days of the warra...

Page 11: ...l 763 a Mount the Model 730A in the equipment rack NOTE If the Model 730 is not mounted in a common rack with the Model 763 a ground wire of 18 AWG or larger must be connected between the two chassis...

Page 12: ...ana jacks J2 and J3 on the Model 730A rear panel These jacks are shorted together when the SCA subcarrier level drops below the threshold set by the SCA MUTE LEVEL control R39 on Board A2 see Section...

Page 13: ...ontrols Connectors and Indicators Front Panel Name FLASHER CAL control PWR switch MAIN CHAN switch SCA INJ switch SCA MOD switch SCA SUBCHANNEL 1 switch SCA SUBCHANNEL 2 switch 3 1 Used peak 3 6 mode...

Page 14: ...SCA subcarrier When depressed allows calibration of all three modes of operation Main Channel SCA Injection and SCA Modulation When calibrating the main channel composite level adjustment the Calibrat...

Page 15: ...t of 32 dB below 100 modulation Three of the switches are marked 1 10 and 100 These indi cate the actual modulation percentage when the meter needle is at the 100 mark For example a meter reading of 7...

Page 16: ...hasis network is switched out of the circuit Lights when the SCA subcarrier is present i e when the SCA subcarrier level is above the threshold set by the SCA MUTE LEVEL control The switches set the p...

Page 17: ...elay to operate an external alarm Adjusts level of incoming SCA signal for the WIDEBAND INPUT Provides an input which bypasses the I F filtering thus providing desireable modulation characteristics su...

Page 18: ...ote Readout Panel Connect 7048 red wire C The same voltage that operates the front panel PEAK MODULATION indicator for operating the corresponding indicator on the Model 7048 brown wire D Ground Conne...

Page 19: ...l 763 press the CAL switch e Adjust the rear panel COMPOSITE LEVEL SET control for a 100 reading on the meter SCA Injection Calibration a Depress the METER CAL switch b Depress either the WIDE or NARR...

Page 20: ...INC SC A MODULATION MONITOR M0DE L 73OA F R CAL MI SUA CAL er J 0 i J II a t J8 uac COMl OSITt IIJPUT COMPOSITE l E EL SCA uec 1 1ANNEL 0 z C A SCA 11 J J CAL o MODEL 730A FCC TYPE APPQQ L NO IA SU 1...

Page 21: ...SCA 1 or SCA 2 selector switch for the desired subchannel g Read the SCA modulation directly on the meter Main Channel Modulation a Depress the MAIN CHAN switch b Depress either the METER or METER sw...

Page 22: ...o a distortion analyzer to measure SCA distortion It can also be used to operate high impedance earphones if desired Either 75 microsecond or 150 microsecond deemphasis can be selected by means of an...

Page 23: ...the Main Carrier to a convenient level of 10 or 31 6 indicated by the Model 730A Now disconnect the Composite Output of the Model 763 from the Composite Input of the 730A and connect the Composite Out...

Page 24: ...through a 15 kHz low pass filter on Board A4 which removes the SCA subcarriers to Meter Amplifier Board Al The main channel modulation is applied to threshold detector where it is compared with a DC v...

Page 25: ...er which has a 3 dB bandwidth of 20 kHz When the NARROW SELECTIVITY switch is depressed both filters are in the circuit and the selectivity is determined by the narrow band filter The filtered SCA sub...

Page 26: ...iscriminator Board A2 so that the SCA modulation delivered to the Meter Amp Board Al is de emphasized When the switch is in the OdB position the de emphasis network is switched out of the circuit The...

Page 27: ...latter two frequencies are applied to a NANO gate whose output is a 33 5 kHz signal gated on and off at an 8 375 kHz rate This calibration signal is fed to the input of the pulse averaging discriminat...

Page 28: ...the top cover three on each side and then remove the top cover Removing six similar screws from the bottom cover provides access to the below chassis components 5 3 Periodic Maintenance Once a year or...

Page 29: ...switch c On the Model 730A rear panel adjust the COMPOSITE LEVEL SET control for a 100 reading on the Model 730A meter The above procedure calibrates the Model 730A main channel measurement circuitry...

Page 30: ...er and an audio generator with a frequency counter a Set the audio generator to precisely 1087 Hz and verify this with a counter Use the 1087 Hz signal to modulate the 67 kHz SCA subcarrier b Observe...

Page 31: ...bleshooting Guides Four troubleshooting trees are presented in Sections 5 7 1 through 5 7 4 as an aid in isolating the causes of a failure To use the guides start at the top and do whatever is require...

Page 32: ...put BAD 0 K Depress the SOdB attenuator button on the f ront pane l and m easure the audio level at the input TP 6 of the meter amp board Al The signal should be approximately 3 5V Peak to Peak 0 K De...

Page 33: ...ly 3 SV Peak to Peak 0 K Depress the OdB attenuator button on the front panel BAO and measure the audio level BAO I Check operation of am pli f i er 28 Lowpass fi l ter L2 L3 and L4 and emitter fol lo...

Page 34: ...y 100 mi ll ivolts peak to peak Check components in 10 7 MHz 1 F I FLl zl FL2 input mixer etc 0 K Look a t 67 kHz level at TP3 on A It shou ld be approximately 130 mil livolts peak to peak 0 K Check t...

Page 35: ...plifier Measure the D C Vol tage at pln6 of z4 on the AZ board It shou1d be between 2 and 3 volts D C BAO Modulating the 67 kHz shouId super impose on A C Signal on top of the I o c Voltage Approximat...

Page 36: ...O I C L SIG LEV 4 SCA MOD CAL SlG I I _J OE EMPHASIS 0 _ SCA t 1JE CTIOIJ M 0 IN C A J JE L I SCA MOWL TIOI J I I I I I I I I SCA1 K L _____ _____ _ 7L __ _ 2 3 4 5 I 5 I I I L __ _ r METe R AMP e dA1...

Page 37: ...P 3 14 15 lo 17 RP 5 18 RP 19 2 0 FP Wl l 5 21 f 5V 22 GND DI SC I C 60B 080o PANEL 0 c i SWG i 2 d l IL J A3 I GND 2 SV 3 FP SWll 5 4 GND 5 CJ 4 Al 8 G f SV 7 RP R 6 2 8 FP SWB Z 9 FP SW 5 0 GNt I FP...

Page 38: ..._ _ _ _ _ _ R FP sw19 1f C 22 IOOO f TPZ C23 220 t R24 IK A 1tA C j ITU fOl t LCVfL C30 2 700pf C I 430pf Q3 2N 3 3 ni I22 opf 4 C __ _ _ 1 _ _ _ _ __ l 14 FR S WI O 1 ev BV t Rn 2SI IK C 2 C3C S 7V...

Page 39: ...1065 1001 Rl l Res Car COllp l 4W 51 5 6K 1065 5601 Rl 2 Res Car Coap l 4W 5 IOK 1065 1002 RI J Res Car Comp I 4W si 18 1065 0018 Rl4 Res Car Cmp I 4W 51 10K 1065 1002 R15 Thennistor 1K 1080 0013 Rl 6...

Page 40: ...IOK R FP SWI R G IK FP CR I 3 9K M JTC J I LEVCL C28 NOTES UNLESS OTHERWISE SPECIFIED 05 I RESISTORS VALU ES IN OlttS 5 1 4 NATT 2 CAPACITORS VALUES IN HICRCFARADS CIH 1 S 7 J INDUCTORS VALU ES IN HI...

Page 41: ...065 0330 R22 Res Car Comp l 4W 5S 151 1065 1502 R23 Res Car Comp l 4W 51 27 1065 0027 R24 Res Car Comp I 4W 5S 2 7K 1065 2701 R25 Res Car Comp l 4W 51 BK 1065 1802 R26 Res Car Comp l 4W 51 27 1065 002...

Page 42: ...le e C35 3 C 5100 f T 105 o o i o l fiL i TE 15V 13 R c c u 12 11 l5t CAI l R I G J 14 ce o uG l R2 FL3 FL f Jc 1 oo 1 22 R41 00 L I m Lt5 w P 4 0 t Q l I l V 21 RI PS rm 15 C34 C4e z 3 f OS o5 Tl T2...

Page 43: ...N 0 2 2 __ ___ 2_2_v 1N l2 oorl 5 v 1 ____________________T 7 2 1 1 5v R 3 J 7815 I Cl l T q CIHI I Cl HI 1 2 CI Hl 8 Cl 3 CRS o h Cle 6ND t C2 7 lt 140 2 11 1 00 2 T F 10 500A l AC 17 CR6 IN li 11 j...

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