General-Electric-Co-440 电路原理图.pdf

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1、MANUAL OF I9S4 MOST-OFTEN-NEEDED RADIO DIAGRAMS GENERAL ill ELECTRIC MODEL 440 (Circuit diagram and other service data on adjacent page at the right.) ALIGNMENT CHART STEP NO. SIGNAL GENERATOR FREQUENCY SIGNAL INPUT POINT BETWEEN TUNING CAPACITOR SETTING ADJUST SEE NOTE NO. AM I-F i 455 kc, 30% mod.

2、 with Pin 1 of V4 (12BA6) thru .02 mf. and chassis Fully closed Primary and secondary cores of T5 for maximum output meter reading. 1, 2, 4 2 400 cycles Pin 1 of V3 (12AU6) thru .02 mf. and chassis Primary and secondary cores of T4 for maximum output meter reading IB lll.l LiMUMHSEMWgni (C4) oscilla

3、tor trimmer for maxi mum output meter reading AM R-F 1500 kc, 30% mod. with 400 cycles Pin 1 of VI (6BJ6) For maximum output meter reading R-f trimmer (C3) for maximum output meter reading while rocking gang condenser 1, 2, 4 5 Inductively coupled to the loop. See Note 3 Adjust antenna trimmer (C2)

4、on loop for maximum 1, 2, 3, 4 6 Pin 1 of V4 (12BA6) thru 100 mmf. and chassis Core of L3 for maximum DC reading at test point on rear of chassis FM- -I-F B 10.7 me unmodulated Pin 1 of V3 (12AU6) thru 100 mmf. and chassis Fully closed Cores of T3 for maximum DC volts at test point on rear of chassi

5、s 5, 10 8 Cores of T2 for maximum DC volts at test point on rear of chassis FM OIS- 9 10.7 me unmodulated Pin 1 of V4 (12BA6) thru Fully closed T6 primary core for maximum DC volts across the volume con trol R104 6, 7, 10 CRIMINATOR 100 mmf. and chassis T6 secondary core for zero DC volts output acr

6、oss volume con trol R104 11 At FM antenna terminals FM oscillator trimmer C2004 for max. DC volts at test point on rear of chassis FM- -R-F 12 108.5 me with built-in FM antenna disconnected Fully open (min. cap.) FMr-f trimmer C2002 for maximum DC volts at test point on rear of chassis while rocking

7、 signal generator frequency 5, 8, 9, 10 ALIGNMENT A-M METER ALIGNMENT NOTES 1. Connect an output meter across the speaker leads to indicate maximum output during AM alignment. 2. Turn the volume control to maximum clockwise position and reduce signal input so that output meter does not indicate more

8、 than Yi watt output during AM alignment. 3. For alignment of the antenna trimmer C2, it is necessary to inductively couple the signal generator output to the loop antenna by connecting a four-turn, six-inch diameter loop of wire across the generator output terminals and locating the loop about one

9、foot from the radio loop. The position of loop should not be changed during alignment to prevent possible errors in peak readings. 4. Set the band switch in “AM* position. 44 F-M METER ALIGNMENT NOTES 5. Connect a vacuum tube voltmeter between the test point on the rear of the chassis and chassis to

10、 read the DC voltage developed at the limiter grid during FMi-f and r-f alignment. Dress the VTVM leads away from the r-f end of the chassis to prevent regeneration. Reduce the signal input so that the VTVM reads approximately 1 volt DC. 6. Connect a VTVM across the volume control to read the discri

11、minator output. 7. To align the primary of T6 (discriminator), detune the secondary core slightly until some DC voltage is read across the volume control, then adjust the primary of T6 for maximum. . For FMr-f alignment, the output impedance of the signal generator should be 300 ohms to properly match the input impedance of this receiver. 9. The cover on the FM tuner must be in place during FM r-f alignment. 10. Set the band switch to the “FM” position. 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN