Philco-Radio-and-Television-Corp-B570 电路原理图.pdf

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1、MANUAL OF 1954 MOST-OFTEN-NEEDED RADIO DIAGRAMS SERVICE HINTS ON PHILCO PRINTED CIRCUITS Although these hints are exact for applicable to other Philco sets using REMOVING THE CHASSIS FROM THE CABINET To remove the chassis from the cabinet, first remove the station selector knob, volume control knob,

2、 and, at the bottom-center of the dial scale, remove the dial scale retaining screw. A flat object (knife blade) placed under the bottom edge will assist in prying the scale out of the cabinet. Pull to remove the pointer from the tuning gang shaft. Remove the screws from the cabinet back, and pull t

3、he back away from the back of the cabinet (use care to prevent breaking the leads from the loop aerial) far enough to reach in and remove the pilot lamp and socket from the re taining clip. Unsolder the output transformer leads from the speaker. Then remove the chassis mounting screws from beneath t

4、he cabinet, and remove the chassis. After removing the chassis from the cabinet re move the subbase, using the following procedure. 1. Remove the output transformer and dial light con nections by pulling the jacks from the pins on the subbase. 2. Unsolder the volume control and a-c switch leads, and

5、 unsolder and remove the loop aerial. 3. At the rear of the panel, bend the hold down tabs out flush with the subbase and remove. Model B570, Code 122, they are printed circuits. PARTS REPLACEMENT Whenever possible, replace all components and leads from the top side of the chassis. In cases where th

6、is is not possible, the components must be unsoldered when removed from the bottom. Use only a light weight low-wattage iron of approximately 22.5 to 25 watts, and always use a low-melting-point solder. Extreme caution must be used to prevent solder from dropping or splashing, and to avoid lifting o

7、f the printed wiring foil. Use only the tip of the soldering iron at the solder point whenever heat is being ap plied Hold the subbase in one hand while applying heat to the solder point and throw the solder off, with a downward thrust, as soon as it starts to melt. When the solder is removed, the p

8、art to be repaired or replaced can be lifted from its located. Insert the new part and secure it with just a drop of solder at each point. To replace tube sockets and i-f transformers, follow the procedure given above for removing solder. Then use a sharp knife to sever the remaining thin bond of so

9、lder at the connections. With the solder re moved, the part can be backed out of the slots. Before inserting the repaired or new part, clean all connections at the unsoldered lugs. Use caution when reinserting parts through the suhbase clots, so that the foil is not lifted. When soldering is complet

10、e apply an electrical varnish to all repaired areas. Base View. Showing Printed Wiring Circuit 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19S4 MOST-OFTEN-NEEDED RADIO DIAGRAMS PHILCO HOME RADIO MODEL B570, Code 121 This data is exact for Model B570, Code 121, and is reproduced through the courtesy of the Phi

11、lco Corp. Model B572. Code 121. is identical. Model B569. Code 121. is very similar. Models B570, Code 122. and B572, Code 122, are also similar, but use printed circuits. See the preceding page for for service data on Philco printed circuits. Clock-type 8 B710 and B711 (Code 121) and B712X (Code 122) are o I Hli similar to these models in the main respect. vw Cl- iO UW o* 42 w r *0 2* jj t/J * Ww * - 9 z 02k w 4|jW n 1/) w ltea I _ij* o* o -Jo*- z OO 30.0 wm X u a. c . I rtr 3 * * a aO ft-r * o H 2 l 2S 1 2 hj 5 J5? in 2* xU t; 1 *T3 E E C X 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN