RCA-Victor-Co-Inc-75X12 电路原理图.pdf

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1、Critical Lead Dress MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS rcaVictor 75X11, 75X12 Chassis No. RC-1050 L_J-+f j ANT. TO GRID I 600-4J9KC I * I Dress all heater leads close to chassis. Dress AVC resistor R4 away from 12SK7 tube socket. Dress diode load resistor R3 away from 12SQ7 tube socket.

2、 Dress 12SQ7 plate resistor R7 over 2nd IF transformer terminal. plate bypass capacitor C17 close to rear of Dress output chassis. Dress power cord lead along rear between 35Z5GT and 50L6GT tubes. 16X- and bottom of chassis VOLTAGES MEASURED WITH RESPECT TO POWER GROUND WITH VOLTOHMY5T OR EQUIVALENT

3、 ANL SHOULD HOLD WITHIN t207u WITH RATED SUPPLY Alignment Procedure RESISTANCES LESS tJL NOT SHOWN , Output Meter Alignment.If this method is used, connect the meter across the voice coil, and turn the receiver volume control to maximum. Test-Oscillator.For all alignment operations, connect the low

4、side of the test-oscillator to the receiver chassis, and keep the oscillator output as low as possible to avoid a-v-c action. Calibration Scale.The tuning dial can not be used for accurate alignment. Use of the procedure given in the alignment tabulation will provide satisfactory calibration. Dial P

5、ointer.With the tuning condenser in full mesh the dial pointer should be adjusted to approx. 17.0 counterclockwise from the vertical position. It should be adjusted before re-assembling the bezel to the cabinet. Dis-assembly.To remove bezel and dial assembly: Remove the four hex head screws in the f

6、eet. To remove chassis from cabinet: Remove bezel and dial assembly described above, remove the pointer by pulling straight to the front, remove four round head screws which hold the chassis to the cabinet. CORD ON INDICATOR DRUM Steps Connect the high side of test-oscillator to Tune test-o sc. to T

7、urn radio dial Adjust the following for max. peak output 1 12SK7 I-F grid through 0.1 mfd. capacitor 455 kc Quiet-point 1,600 kc end of dial L8 and L9 2nd I-F transformer 2 Stator of C2 through 0.1 mid. L8 and L7 1st I-F transformer 3 Ant. lead in series with 200 mmid. 1,620 kc full clock wise C3 (o

8、sc.) 4 1,400 kc 1,400 kc Cl (ant.) 5 600 kc 600 kc A Band L5 (osc.) Rock gang 8 Repeat steps 3, 4 and 5. 106 * Do not readjust L8 or L9 when test oscillator is connected to C2. _ LOOP ANTENNA*_j. SHOWN WITH DANG CONDENSER AT MAXIMUM CAPACITY 3 TURNS Dial-Indicator and Drive Mechanism Tube and Trimmer Locations 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN