Emerson-Radio-and-Phonograph-Corp-725A 电路原理图.pdf

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1、MANUAL OF 1953 MOST-OFTEN-NEEDED RADIO DIAGRAMS MODEL - 725A Tmerson Radio CHASSIS - I20I49-A DISASSEMBLY INSTRUCTIONS 1. Remove two push-on knobs at front of cabinet. 2. Disconnect phono-motor leads by unscrewing wirenuts. 3. Remove phono pickup plug. 4. unscrew two front cabinet feet and two chass

2、is bolts at sides of cabinet. Lift out chassis. 5. Remove two base plate screws at center of chassis. CONDITIONS FOR VOLTAGE AND RESISTANCE READINGS 1; Voltages indicated are positive d.c., resistances are in ohms, unless otherwise indicated. 2. Measurements made with voltohmyst or equivalent. 3. Li

3、ne voltage maintained at 117 volts a.c. for voltage measurements. 4. Socket connections are shown as bottom views, with measurements from pin to common negative. 5. Volume control at maximum, for voltage measurements. 6. Nominal tolerance on component values makes possible a variation of 15* in volt

4、age and resistance readings. 7. on the diagram, upper values are voltage and lower values are resistance. NC denotes no connection, K is ki 1 ohms, MEG is megohms, inf is infinity. Resistances marked * are measured to pin 8 of recti fier (B+). VOLTAGE 4 RESISTANCE READINGS FOR CHASSIS 120149-A V-l I2SQ7 V- 2 50L6GT V-3 3SZSGT 0 0 0 0 MO AC NC 0 1 t zM5o- l W6v 0 0 300 K 93 0 00 AC 230 117 AC 108 AC I4MEG.T o_ INF 0 ) 0 1_50 600 K 12 AC IKK 93 160 * 32 AC rer n 140 NC 220 NC 105 Z60 J 103 1 K 80 AC 0 10 I4J 0 * 180 O OO I2SQ7GT 50L6GT 35Z5GT FRONT 收音机爱 好者资料库 RadioFans.CN