RCA-Victor-Co-Inc-RC-1057A 电路原理图.pdf

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1、MANUAL OF 1949 MOST-OFTEN-NEEDED RADIO DIAGRAMS rca Victor 77U Radio-Phonograph Combination Chassis No. RC-1057A CAUTION.CLOSE TUNING CONDENSER PLATES COMPLETELY (C-C-W) BEFORE REMOVING CHASSIS FROM CABINET. Take off both wooden strips on bottom of cabinet by removing wood- screws before loosening c

2、hassis bolts. Dial Painter Adjustment.Rotate tuning condenser fully counter clockwise (plates fully meshed). Adjust indicator pointer so that it is 3% from the left hand edge of the dial back plate. Tubes 6C4 and 6AQ6 may be replaced by removing the sloping panel (remove four wood screws) in the fro

3、nt of the record changer com partment. Before removing the chassis from the cabinet it is advis able to loosen the two hex screws holding the speaker horizontally. This will allow the chassis to be removed and replaced easily. When the chassis is, replaced the dial lights should be adjusted so as no

4、t to be visible from the front of the cabinet, and yet to give correct dial lighting. Move the speaker so it is flush against the baffle before retightening the hex nuts. The chassis mounting hoard should be Hush against the front of the cabinet, and the chassis mounting holes should be centered ove

5、r the holes in the board. The first l-F transformer shown in the schematic is stamped 970441-1. Same chassis will have a first l-F transformer stamped 970441-5. Con nections to this alternate transformer are as shown in the black letters. Performance will be identical far bath sets. Output Meter.Con

6、nect meter across speaker voice coil. Turn volume control clockwise to radio maximum high position (3) for alignment. St*p Connect the high side of test- oscillator to Tune test-osc. to Turn radio dial to Adjust tho follow ing for max. peak output I.F. grid, in series with .01 mfd. 455 kc Quiet poin

7、t 1,600 kc end of dial Pri. 4 Sec. 2nd I.F, transformer 2 1st Dot. grid in series with .01 mfd. Pri. 4 Sec. 1st I.F. transformer NOTE.-ANTENNA LOOP AND RECORD CHANGER MUST BE IN CABINET 3 Antenna terminal in series with 220 mmfd. 1,600 kc 1,600 kc C7 (OM.) 4 1,400 kc 1,400 kc C4 (ant.) 5 600 kc 600 kc Osc. Coil 12, L3 Rock gong 6 Repeat stops 3, 4, 4 5 if necessary Test Oscillator.Connect high side of teet oscillator as shown tn chart, Connectlow side through a .01 mf capacitor to common “B”. Keep the output signal as low as possible to avoid a-v-c action. 收音机爱 好者资料库 RadioFans.CN