Howard-Radio-Co-780 电路原理图.pdf

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1、MANUAL OF 1941 MOST POPULAR SERVICE DIAGRAMS 5PKR PR.AME CNDED AS SWITCH IS SET TO HIGHER FREQUENCY BANDS THE SECONDARY COILS OF THE LOW FREQUENCY BANOS ARE SHORTED OUT 6AVC. POR EXTRA SPEAKER Vai/JJb2e- Gowda way 3-4270 To no S VoO Cont. 722&l Elect Gond. C,CgC3 14 _ Howard Radio Wave-Band Switch P

2、osition Position of Dial Pointer Generator Frequency Broadcast Max. Cap. 465 KC 7-22 IE 21 21 MO 2.2-7 MO 6 6 MO 2.2-7 MO 2.2 2.2 MO Broadcast 1400 1400 KC Broadcast 600 600 KC praisin 83-938 *+T_ 11r VOLTS 6 ALIGNMENT PROCEDURE Generator Connection Converter Grid Ant. (Brown) MODEL 780 nwr. NO. C60

3、-7I5 j)Q-2&-40 See Fig. 1 and Fig. 2. Trlmmers Adjusted (In order shown) i1ji2I3I4 05 P9 OlCUAll Pl2 Trimmer Function IF Osc.jAnt. Osc.,Ant. Osc.Pad. Osc.jAnt. Osc.Pad. A-Each step it the alignment should be repeated in the from Signal Generator low. The I.F. trimmers are reached frequency. For exam

4、ple, if the adjust- nerSorIt $g TthwfifwiS hfaf 2,000 less 930 KC or about 20,070 TOC-When adjusting this pad, move the tuning hand back and forth and adjust padder until the peak of greatest lnD-Sef thltthf ?ming hand is set exactly on the last line above 540 when the condenser is at maximum T, I F

5、UNCTION C$ I 1 PLATE | I I TUBE | FUNCTION | C | | PLATE | | 6SK.Y K.f . gyj 6SA7 Mixer 6SK7 I.F. Amp. 6SK7 I.F. An. 6SQ7 Diode-AVC 6V6GT Output 12.5 80 Rect._ 6U5 Tuning Eye 265 120 V. Voltage taken from ground with line voltage at - 120 V. High voltage reading off rectifier - 325 V. Drop across speaker field - 58 V. Voltage taken with 1,000 Ohm per volt meter. Band Switch in BC position except R.F. Stage measurements. COMPILED BY M. N. BEITMAN, SUPREME PUBLICATIONS 61 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