Midwest-Radio-Corp-1739 电路原理图.pdf

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1、收音机爱 好者资料库 RadioFans.CN Trim, TWftti mo TKtM 0f 0f firOtmd SSO/SOOHC BBmtd * MC. AZ tl MC DBvrM / - MC ZSmnA iZS- J30 KC. aC/LLATO/t PLATE Instructions for Aligning 5 Band 1939 Midwest Sets. FRONT of 6T Remove the oscillator tube. Peak I.P.s at 456 KC. for maximum gain, while AFC is off. Receive a s

2、ignal from generator, turn on AFC. If tuning is disturbed, realign: secondary side of AFC trans former. Re-adJust trimmer across the primary of the APC transfor mer until maximum APC voltage is developed. May be measured with voltmeter from cathode of 6J7 APC control tube to ground. Band A 550 to 15

3、00 KC. Padded at 550 KC. and trimmed at 1400 KC. R.F. and mixer trimmers should be adjusted at 1400 KC. Band B 1.5 to 4.2 MC. This band should be padded at 1.7 MC., and trimmed at 4.0 MC. Band C 4.2.to 12.0 MC. This band has a fixed padder and should be trimmed 11.0 MC. Band D covers from 12 MC to 3

4、0 MC. and should be trimmed at 29 MC. mere for maximum gain at 29 MC, This band has a fixed padder Adjust R.F. and mixer trim- Band E covers from 125 to 350 KC. (long wave). This band should be padded at 135 KC. and trimmed at 340 KC. A dummy antenna,- consisting of a 200 ohm resistor and 10 mmfd. condenser in parallel, should be connected in series with cnt of signal generator. COMPILED BY M. N. BEITMAN. SUPREME PUBLICATIONS output 收音机爱 好者资料库 RadioFans.CN