Admiral-Y3083 电路原理图.pdf

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1、10 8 DASHED LINE INDICATES ADJUSTMENT FROM UNDERSIDE OF CHASSIS 收音机爱 好者资料库 RadioFans.CN VOLUME R-21, MOST-OFTEN-NEEDED 1961 RADIO SERVICING INFORMATION ARA/TTD AT chassis sv 5, model Y3083 / I ) lvl I I / I J Alignment Procedure, Continued ALIGNMENT USING AM SIGNAL GENERATOR AND VTVM Allow set and t

2、est equipment to warm up for approximately 15 minutes before alignment. Use an isolating transformer or insert a .01 mfd capacitor in series with the high side of signal generator. DO NOT CONNECT AN EARTH GROUND TO THIS RECEIVER. Connect a short wire jumper from the center point of C30 to chassis. (

3、To short L8 to chassis ground.) 1 Set signal generator for 400 or 1000 cycle modulation, 30%. Set volume control full on. Keep signal, generator output low to prevent overloading. Turn bias control, (R10) to full counterclockwise position (maximum bias point). Connect the VTVM across output transfor

4、mer secondary (voice coil leads). Use the 1.5 volt AC scale for output readings. NOTE: If available, a commercial output meter is more desirable for this purpose. Disconnect voice coil leads and use a 3.2 ohm load. Use nonmetallic alignment tools. Use hex tool (Admiral part no. 98A30-7) for transfor

5、mer adjustment slugs. STEP SIGNAL GENERATOR CONNECTION SIGNAL GENERATOR FREQUENCY RECEIVER GANG SETTING ADJUSTMENT FOR MAXIMUM 1 Totf Point W (Center Point of Cl 2) 10.7 MC Fully open A, B, C, and D 2 Set trimmer! J end K one tarn from tight. Set adjustment screw (H) Vi inch above chattit. 3 Antenna

6、. (Canter point of C2 through 7S ohm resistor.) 87.S MC Fully doted (set indicator dial on and mark) E, *F, and G 108 MC 108 MC 108 MC Fully doted 108 MC H, J, K and L Touch-up E Touch-up H, J and K Soma os stop 3 Soma dt stop 3 Soma at step 3 a. Sot up equipment at in step 1 above. b. Remove ihort

7、acrott L8 and adjuit M for maximum ouput. c. Adjuit N (R10, itorting from full clockwite potition) to the first point of maximum tound. Ute weakoit tignal pottibla. OPTIONAL METHOD FOR STEP 7 a. Diiconnoct tignal generator from receiver. b. Remove wira jumper from acrott L8 (C30 to chassis ground).

8、c. Tuna in a vary weak tignal, or reduce tignal level, until a itrong hitt it heard in the teund. (If nocattary coil up antenna in a ball or ihort antenna lead te chattit or both.) d. Adjuit M (quadrature coil, L8) for maximum output. a. Adjuit N (R10) for maximum output and dearoit tone. IF ALIGNME

9、NT CHECK USING SWEEP GENERATOR AND OSCILLOSCOPE a. Use the same equipment setup as in step 1 but add the oscilloscope (vert, input) connected to test point “X”. b. Use a wideband sweep, unmodulated for response check, except the final adjustment given in step e. c. Sweep generator signal injected at

10、 the same points as given in steps above. Coil (L3) is adjusted by squeezing or spreading turns of the coil. CHASSIS REMOVAL To remove the chassis from the cabinet it is neces sary to remove only the rear cabinet section, since the front panel and knobs are attached to the chassis. 1. Turn set botto

11、m side up and using a screw driver, d. Oscilloscope pattern should be a typical response curve. Adjust as in step 1 for best symmetry as well as maximum gain. e. Final Adjustment: With generator connected as in step 4, and dial set to 108 MC; use 75 KC sweep and 400 cycle modulation. Remove short fr

12、om across L8. Adjust M and N for maximum output, using minimum signal input. force chassis forward by pushing on the front panel section visible through the elongated chassis mount ing holes. A small elevation is provided on the section of the panel inside this slot for this pur pose. After the AC interlock connection has been broken, the chassis with the front panel attached will slide forward easily and out of the rear section. 15 收音机爱 好者资料库 RadioFans.CN