General-Electric-Co-C405A 电路原理图.pdf

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1、VOLUME R-19, MOST-OFTEN-NEEDED 1959 RADIO SERVICING INFORMATION GENERAL ELECTRIC COMPANY Models C405A, B, C406A, B SPECIFICATIONS TO REMOVE CHASSIS CABINET: Model C405A,B-Gray and White Mode1 C406A,B-Pink ELECTRICAL RATING: 105-120 volts AC 30 Watts (9117 Volts AC OUTPUT: Undistorted .9 Watts Maximu

2、m 1.5 Watts GENERAL INFORMATION Remove the volume control knob. Take out the four hexhead screws, one on each corner of the chassis board and one hexhead screw below the tuning con denser. Unsolder the one wire to switch on the clock and one to the clock motor. Close the tuning condenser Cl, and wit

3、h the thumb and forefinger grasp the condenser and pull. The chassis will separate from the tuning knob which is left attached to the cabinet front. The main difference in the A and B versions of the C405 series of clock-radios is the oscillator- converter stage (Vl). The A version uses a 12AU6 tube

4、 as VI and the B version uses a 12BE6 as Vl. The Vl stage for the B version is shown as a separate stage on the schematic. The tuning knob is held to the cabinet and can not be removed without first removing the chassis. SERVICE NOTE Always use an isolation transformer when servicing or aligning thi

5、s receiver to protect personnel and test equipment. When aligning, keep the signal input low so the AVC will not affect the output. TO REMOVE CABINET FRONT Remove the two screws located on each side of the cabinet back; unscrew the clock set knobjseparate the cabinet front from the back. When separa

6、ting the cabinet, the speaker leads must be unsoldered before complete separation of the cabinet can be ac complished. The speaker is mounted on the cabinet back with the radio chassis and clock mounted on the cabinet front. TO REMOVE THE CLOCK Separate the cabinet as described above. Unsolder the t

7、wo leads, one from the switch to the circuit board and one from the clock motor to the circuit board. Remove the two screws holding the AC interlock to the cabinet. Remove the two clock knobs. Snap out the clock crystal starting from the left side. Then, remove the two nuts holding the clock to the

8、cabinet and remove the clock. TROUBLESHOOTING Excessive loudness when adjusting the volume level to minimum is caused by excessive capacity be tween terminals 2 and 3 of RCW-3207. The excessive capacity can be eliminated without replacing the couplate or by removing the circuit board in the followin

9、g manner: 1. Clip off couplate lead #3. 2. Solder a 220 mmf. capacitor (Cat. No.RS-1203) across the two outside terminals of the volume control- located on the component side of the chassis board. i ADJUST FOR MAX-(f455KCl V3 I24V6 DET- AUWO AMP ADJUST FOR MAX. 1500 KC WHILE ROCKING GANG- , !r4f - Y

10、 iTilg3QT 11 ADJUST FOR MAX. 1620 KC GANG FULLY OPEN. VI (0 VCRSK I2BE6 9V UNLESS OTHERWISE NQTSO CAPACITORS MORE THAN I MMF CAPACITORS LESS THAN I MF RESISTORS ARE 1/2 WATT K 1000 M *1,000.000 DC VOLTAGES |7V LINE TO B - WITH 20.000 A/VOLT METER oxzui) OTTOM VIEWS V VERSION* V VERSION i V .s S) MODELS C405A.B C406A.B SET VOLUME CONTROL AT MAXIMUM CONNECT OUTPUT METER OR SCOPE ACROSS VOICE COIL INDUCTIVELY COUPLE SIGNAL GENERATOR TO RECEIVER 47 收音机爱 好者资料库 RadioFans.CN