Emerson-Radio-and-Phonograph-Corp-746B 电路原理图.pdf

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1、收音机爱 好者资料库 RadioFans.CN MANUAL OF 19S4 MOST-OFTEN-NEEDED RADIO DIAGRAMS EMERSON RADIO AND PHONOGRAPH CORPORATION Model 746B, Chassis 120177-B (Continued from the adjacent page, at left) ALIGNMENT PROCEDURE 1. Volume control should be set at maximum position. The output of the signal generator should

2、 be no higher than necessary to obtain an output reading. Attenuate the signal input as alignment proceeds. 2. Use isolation transformer if available; otherwise when connecting low side directly to B neutral use a .1 mfd. condenser in series with low side of signal generator. 3. Refer to figure 3 fo

3、r location of alignment trimmers. 4. For SW alignment of the receiver, maintain the telescoping antenna closed. Step SIGNAL GENERATOR Band Switch Position Dial Setting Adjust Procedure Coupling Frequency i High side thru 0.1 mfd. to grid (Pin No.6) V-2, 1L6. Low side to B neutral (See note 2 above).

4、 455 KC BC Tuning Cond Fully open T-2,T-l Top and Bottom Peak for maximum output. 2 Form loop of several turns and radiate signal into receiver. 1640 KC BC n C -24 (BC CSC.) * 3 n 1420 KC BC Tune for maximum output Cl (BC Ant.) C-13 BC (RF) * 4 _i it 530KC BC Tuning Cond. Fully Closed C-22 (BC pad-

5、der L-4 (BC. RF) Recheck steps 2 to 4 and retune if necessary 5 High side thru a 200 MMF to ex ternal antenna terminal, low side to chassis. 6.5 MC. SW-1 TuningCond Fully open C-25 QSC. Peak for maximum output * 6 it 5.5 MC SW-1 Tune for max. output C-5 (Antenna) C-14,(RF) * 7 n 22.0MC SW-2 Tuning C

6、ond Fully open C-26 OSC. * 8 n 21.5 MC SW-2 Tune for max. output C-6 (Antenna) C-15,(RF) Rock dial each side of 21.5 MC. while adjusting C-6 and then C-15 for maximum response * Note underside chassis cover must be secured in place when performing steps 2 to 8, otherwise tuner tracking will shift. R

7、ESISTANCE READINGS FOR CHASSIS 120177-B SYMBOL TUBE PIN 1 PIN 2 PIN 3 PIN 4 PIN 5 PIN 6 PIN 7 V-l 1U4 25 4 K 4 K 2 MEG. N.C. 3 MEG. 40 V-2 1L6 14 4 K 4 K 210 K 50 K 3.5 MEG. 25 V-3 1U4 40 5 K 5 K N.C. 40- 3 MEG. 55 V-4 1U5 0 4.2 MEG. 4 K 14 - 1 3V4 55 4 K 4 K 0 65 75 V-6 Selinium Rectifier PLUS FROM CHASSIS AND BRiNG LINE CORD OUT THROUGH NOTCH IN SIDE OF RACK COVER. Figure 2. Tube and Battery Location Diagram Figure 3. Alignment Point Drawing 收音机爱 好者资料库 RadioFans.CN