Emerson-Radio-and-Phonograph-Corp-843 电路原理图.pdf

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1、VOLUME R-16, MOST-OFTEN-NEEDED 1956 RADIO SERVICING INFORMATION tL C-13 _TK)OMFD. ALL CAPACITORS LESS THAN I IN UFOS ANO ABOVE I IN MMFD*S UNLESS OTHERWISE SPECIFIED. 6 V 67.5 V few CAUTION A* BAT. T B* BAT. Use only a vacuum tube type of ohmmeter. The R x 10 scale must be used for all forward (low)

2、 resistance mea surements* Do not use the Rxl scale as this might damage the transistor. A shunt type ohmmeter should not be used. If in doubt as to the type of vacuum tube ohm meter you have, place a 1,000 ohm resistor in series with it and subtract this 1,000 ohms from the reading obtained. If the

3、se instructions are not followed, damage to the transistors may result since some non-electronic type orf ohmmeters use high internal battery voltages. INVERSE HIGH RESISTANCE FORWARD LOW RESISTANCE CONDITIONS FOR TAKING VOLTAGE READINGS Voltages indicated are positive d.c., resistance is ohms, unle

4、ss otherwise noted. Measurements made with voltohmyst or equivalent. All measurements taken between points and chassis, unless otherwise indicated. Before taking resistance measurements, turn on-off switch to the off* position (or disconnect batteries). Then remove transistors. Volume control at max

5、imum, no signal applied for voltage measurements. Nominal tolerance in component values makes possible a variation of + 15% in readings. K is Kilohms, MEG in megohns. ALIGNMENT INSTRUCTIONS Volume control should be at maximum; output of signal generator should be no higher than necessary to obtain a

6、n output reading. Use an insulated alignment screwdriver for adjusting. DUMMY ANTENNA SIGNAL GENERATOR COUPLING SIGNAL GENERATOR FREQUENCY RADIO DIAL SETTING OUTPUT meter ADJUST REMARKS .1 mfd. High side to orange leod of bar loop an tenna. Low side to ! chassis. 455 KC. Tuning con denser fully open

7、. Across voice coil T2, T3 and T1 Adjust for maximum output starting with T3. Use a loop set per pendicular and about 20 from center of bar loop ant. in set. 1620 KC. Tuning con denser ful ly open. Across voice coil C-2 (osc. trim mer) Fashion loop of sever al turns of wire and radiate signal into b

8、ar loop of receiver. Ad just for maximum output. M 1400 KC. T une for maximum output. Across voice coil. C-l (Ant, trimmer) Adjust for maximum output. 1* 600 KC. Tuning con denser set for 600 KC. Across voice coi 1. Osc. slug in L-2 Rock the variable cond. each side of 600 KC while adj.osc. slug for max. response. 1620 KC. Tuning con denser fully open. C-2 Osc. trim mer. If readjustment is ne cessary repeat steps 2 to4 until nofurther im provement is noted. 36 收音机爱 好者资料库 RadioFans.CN