Sears-Roebuck-and-Co-20 电路原理图.pdf

《Sears-Roebuck-and-Co-20 电路原理图.pdf》由会员分享，可在线阅读，更多相关《Sears-Roebuck-and-Co-20 电路原理图.pdf（6页珍藏版）》请在收音机爱好者资料库上搜索。

1、6V6-GT MANUAL OF 1950 MOST-OFTEN-NEEDED RADIO DIAGRAMS Sears , Roebuck and Co. Chassis 132.877, Catalog Nos. 18 and 20 (Alignment information is given on the next page) You will find Model 9022, Chassis tH? 132.871 almost identical; while jH*- Model 9105, Chassis 132.875 uses /So type 6AQ5 output tu

2、be and has a record changer. 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1950 MOST-OFTEN-NEEDED RADIO DIAGRAMS Soars, Roebuck and Go. Chassis 132. 877, Catalog Nos. 18 and 20. Position Generator Dummy AM ALIGNMENT Generator Generator Adjust Trimmer Trimmer of Frequency Ant. Connection Connection In Order Show

3、n Function Variable Open 455 Kc .05 mfd. (high) Mixer Grid Ground Lead Chassis For Max. Output Al, A2, A3, A4, I.F. Open 1650 Kc eTest Loop Test Loop A5 Oscillator 1400 Kc 1400 Kc eTest Loop Test Loop A6 Antenna e*600 Kc 600 Kc Test Loop Test Loop Check Point Antenna Connect generator lead to a Stan

4、dard Hazeltine Test Loop. Model 1150, placed two feet from the set loop, or three turns of wire about six inches in diameter, placed about one foot from the set loop. Or the generator can be connected with the high side lead to the AM antenna screw terminal and the ground lead to the chassis. e* Wit

5、h a generator signal of 600 Kc, tune the set to the point where maximum output is obtained, which should be ap proximately 600 Kc on the dial. Adjust anteni|a section places of variable for maximum output. FM ALIGNMENT Detector and I.F. alignment using Signal Generator and Oscilloscope. 1. Connect F

6、M Generator, High side, to grid (pin 1) of 6BA6 2nd I.F. tube through .005 mfd. dummy. 2. Set generator frequency to 10.7 Me. modulated either 60 cycles or 400 cycles, 250 Kc sweep (125 Kc. deviation). 3. Connect vertical input of scope across volume control of receiver (grounded terminal to chassis

7、, ungrounded terminal to high side of control). 4. Set scope switch for internal synchronization and set horizontal oscillator to 2X frequency of modulating voltage of generator. (120 or 800 cycles) 5. Turn variable condenser fully open, and band switch to right (FM). 6. Adjust frequency vernier of

8、horizontal oscillator on scope until the pattern becomes stationary. 7. Adjust ratio detector primary slug No. A7 for maximum vertical sweep of the scope pattern. 8. Adjust ratio detector secondary slug No. A8 to center the cross over point of the pattern. Pattern should look like Fig. 1 with the sa

9、me amount of curve on both ends, and the cross over point in the center. 9. Connect generator, high side, to center antenna screw terminal on Dot tom of chassis. 10. Adjust I.F. slugs A9, A10 and All for the greatest vertical sweep of the pattern, consistent with linearity. If the I.F. slugs are adj

10、usted for maximum sweep of the pattern, the pattern may become non-linear. Therefore, adjustment should be made for the greatest sweep which can be ob tained and still have all four ends of the X” pattern similar in size and shape. 11. Check the alignment of the I.F. and detector circuits by varying

11、 the signal generator frequency above and below the center frequency of 10.7 Me. If the receiver is perfectly aligned, two smaller X” patterns of similar size and shape will result, one on either side of the center frequency. See Figure 2. X PATTERN CENTER FREQUENCY SMALL X RkTTERN ABOVE mo BELOW CE

12、NTER FRC0UBSCY Position of Generator Dummy Generator Connection Generator Connection Adjust Trimmers Trimmer Variable Frequency Ant. High Side Ground Lead In Order Shown Function Fully Open 108.5 Me. *300 ohm Ant. (FM) Terminal Ground (C) Terminal A12 Oscillator Fully Closed 87.5 Me. e300 ohm Ant. (

13、FM) Terminal Ground (C) Terminal Check Point Oscillator 105 Me. 105 Me. *300 ohm Ant. (FM) Ground (C) A13 ILF. 91 Me. 91 Me. *300 ohm Terminal Ant. (FM) Terminal Terminal Ground (C) Terminal Check Point ILF. For R.F. alignment use FM generator signal modulated with 400 cycles 45 * The 300 ohm dummy should be made up to two 150 ohm resistors, one Ke. sweep (22.5 Kc.) deviation). placed in each lead at the receiver antenna terminals 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN