Hoffman-Radio-Corp-A700 电路原理图.pdf

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1、MANUAL OF 1948 MOST-OFTEN-NEEDED RADIO DIAGRAMS an RADIO CORP. MODEL A700 CHASSIS UOS L F. Alignment 1. Connect output meter across speaker voice coil; set meter on 1-volt scale. 2. Connect output of signal generator to trimmer C3 (blue wire on trimmer located at rear of chassis). The ground side of

2、 the signal generator should be connected toB- through a .1 Mfd. condenser. Set signal generator on 455 Kc (modulated). 3. Adjust I.F. trimmers (first T2 and then Tl) for maximum reading on output meter. NOTE: Keep signal level low, just enough to keep- the maximum reading on the output meter at 0.4

3、 volt or less, tuning gang should be set with plates all the way out; volume control full on. 4. Replace bottom cover plate. R. F. Alignment 1. Leave tuning gang with plates all the way out. 2. Set signal generator on 1650 Kc (modulated) and feed generator output into a loop of wire approximately 6

4、in diameter. Place the loop about one foot away and parallel to the receiver loop antenna. 3. Tune in signal by adjusting oscillator trimmer C7. 4. Adjust output of signal generator to obtain deflection of .4 volt or less on output meter. 5. Adjust oscillator trimmer for maximum output. 6. Set Signa

5、l generator to 1400 Kc and tune in signal with tuning condenser. 7. Adjust loop antenna trimmer Cl and R. F. Coil assembly for maximum output. The R. F. coil adjustment is made by loosening the coil mounting clamp and sliding the coil up or down as required. 8. Set signal generator and tuning gang t

6、o 600 Kc and adjust R. F. trimmer C3 for maximum output. 9. Go back to 1400 Kc to check tracking and readjust at 1400 Kc and 600 Kc as required. SYMBOL DESCRIPTION Hoffman No. C1-C7 TrimmersPart of Variable Condenser C2-C6 TwoSeeHbti 1388-180 Mmf.l 4401 C3 60-260 MmM. Mica Trimmer 4306 C4-C9-C11 .00

7、01 Mfd. Mica 4000 C5 47 Mfd. Mica 4009 C8-C26 .01 Mfd. 400 Volt Tubular Paper 4112 C10-C12- .005 Mfd. 600 Volt Tubular Paper 4102 C13-C14 C15-C16 100 Mfd. 25 Volt Dry Electrolytic 4204 C17-C19- .05 Mfd. 200 Volt Tubular Paper 4100 C20-C21 C18-C25 Dry Electrolytic Condenser (30-50 Mfd. 150-150 Volt)

8、4201 C22-C23 .2 Mfd. 200 Volt Tubular Paper 4108 C24 .05 Mfd. 400 Volt Tubular Paper 4101 LI Autenna Loop 55208 L2 Antenna Loop Compensator 5250 L3 R.F. Coil Permeability Tuned 5245 L.S. SW* P.M. Speaker 9019 R1-R14 3.3 Megohm, Vi Watt 4535 R2-R7-R9- 2.2 Megohm, Vi Watt 4502 R16 R3 680 Ohms, Vi Watt

9、 4514 R4 .47 Megohm, Vi Watt 4506 R5-R15 1 Megohm, Vi Watt 4513 R6-R10 .1 Megohm, Vi Watt 4511 R8 3900 Ohms 10%, Vi Watt 4527 R11 1 Megohm Potentiometer with D.P.S.T. Switch (Volume) 4808 R12 10 Megohm, Vi Watt 4505 R13* 820 Ohm 10%, Vi Watt 4533 R17 1500 Ohm, Vi Watt 4534 R18-R22 47 Ohm, 2 Watt 453

10、2 R19 1000 Ohm, 1 Watt 4522 R20 1500 Ohm, 6 Vi Watt 5 % Wirewound 4701 R21 470 Ohm, 1 Watt 10% 4531 SI AC/DC Battery Switch Plug Operated 6010 S2 On-Off Switch (on Volume Control) Tl Input I.F. Transformer (455 K.C.) 5242 T2 Output I.F. Transformer (455 K.C.) 5243 T3 Output Audio Transformer 5104 T4

11、 Oscillator Coil 5244 Rect. Selenium Rectifier 9517 * Semo sets use 1000 ohms 20%, Vi Watt, Part No. 4542. The following table lists the normal operating voltages to be expected at the various socket terminals. PIN NO. I 2 3 4 5 6 7 1T4 (RF) 2.6 84 65 2.6 3.9 1R5 1.3 84 64 -5.0* 1.3 3* 2.6 1T4 (RF)

12、3.9 84 65 1.2* 3.9 1.5* 5.2 1S5 1.3 0 .5* 20* 1 .5* 0 3Q4 5.2 84 1.3* 84 6.5 84 7.8 NOTE: All voltages are measured with reference to B- (black wires on volume control switch) and no signal in put to receiver. * These readings must be taken with a V. T. V. M. C2I t CMC TCI9 Cl7 PS2-ON VOLUME CONTROL 71 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN