Emerson-Radio-and-Phonograph-Corp-921-D 电路原理图.pdf

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1、VOLUME R-20, MOST-OFTEN-NEEDED 1960 RADIO SERVICING INFORMATION EMERSON RADIO Chassis 908-B, Chassis 120466B, material exact for this set. Model 909-B, Chassis 120468B: Model 912-B. Chassis 120480B: and Model 921 -D. Chassis 120495B. are all electrically similar to 908-B and the impor tant differenc

2、es are explained on pages 38, 39, where material is continued. i .,t ini ju T7 it; . JO O Oj -= l 2E S .2-0 =tS| *1 s iKir J _ jK s 2?X v nrt sliS-Uii ) i* w V.JIM- -=-Lwh.- T* I T8 l t x. I( i AV!wL- s ss i UjU L. *a s ri pq r *1*i ,i*s -1 it-*: ) is. 1/ B fW V*/ j? Tai S , 5 ? . Z - Q. OD = C o 2

3、0) 5 OP = U. 5 T3 3 j = 2 * =50 ,_020 ? O C r # y c E y E D u * 3 S I i - 81 si-s! s o i |exi t- g| g 3t 1 5 ooiSq-j iwilz.zk o * 37 收音机爱 好者资料库 RadioFans.CN VOLUME R-20, MOST-OFTEN-NEEDED 1960 RADIO SERVICING INFORMATION 38 收音机爱 好者资料库 RadioFans.CN VOLUME R-20, MOST-OFTEN-NEEDED 1960 RADIO SERVICING

4、INFORMATION FM ALIGNMENT (Using RF Generotor AFC(SW-4) in Off Pos. EMERSON RADIO |_ SIGNAL GENERATOR VTVM FM RECEIVER REMARKS nno_D nnn t 5tP c_ Ir-_ I 171 . u . 7 I m- Models 908-B, 909-B, 912-B, and 921-D, Chassis 120466B, 120468B, 120495, continued from pre vious two pages. PRELIMINARY ALIGNMENT

5、INSTRUCTIONS _ NOTE: Be sure that the dial pointer is physically aligned (Re. Fig. 4a AFC(SW-4) in Off Pos. FM RECEIVER REMARKS _Adjust_ Turn out top slug of Indication is obtain- ratio lFxfmr(T-6) able without slug until greatest peak touching top of on VTVM is indicat* IF can. ed. 10.7 MC (no swee

6、p) metal can of electro* lytic filter. Peak in following Order; 1. Top 1 st IF (T-7) (rear of tuner). 3. Bot. slug of Ratio | F(T*6) Adjust for maximum output on VTVM Adjust Carefully turn in top Varying freq. above V/lFAMP & feTU I I- AM 9% INCHES FMl0 3/4 inches PHYSICAL TRACKING 7. POiNT 1 (340KC

7、) I DUAL-CHANNEL SW-2 LOUONESS CONTROl FUNCTION FM TUNING SHAFT WHEEL *8* SW|TCH BASS CONTROL CHAIN DRIVE (BEAO CHAIN) TREBLE-ON-OFF SHAFT (PULL-ON, PRESSOFF) FIGURE 4 A, B, C - DIAL CORD, BEAD CHAIN STRINGING TUBE LOCATIONS AND ALIGNMENT POINTS PARTIAL REMOVAL OF FM TUNER FOR LIGHT FIELD SERVICING

8、(Re. Fig. 5) 1. Remove the tube adjacent to the front of the tuner housing. 2. Unsolder the ground side of the disc capacitor and the tuner ground strop (left front of tuner). 3. Unsolder wires and components with the exception of the two Capri stors and the coaxial lead. 4. Remove the two hexagonal screws which mount the FM tuner to the front of the chassis. Finally, un solder the spot-soldered ground on the bracket to com pletely disengage the tuner from the chassis. 5. Extend connections with jumper wire. 6. The tuner shield cover slides off the reor. 39 收音机爱 好者资料库 RadioFans.CN