Stewart-Warner-Corp-9151-A 电路原理图.pdf

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1、MANUAL OF 19S0 MOST-OFTEN-NEEDED RADIO DIAGRAMS 0 (FM) 1.1 . 10.7 MC. (AM) 1. F. 455 KC. STEWflRFRUARIIER AM-FM RADIO MODEL 9151-A HOW TO REMOVE CHASSIS FROM CABINET 1. Remove all knobs by pulling them forward. 2. Take off dial scale by pressing down on top center of plastic dial enclosure and at th

2、e same time pulling it forward. 3. Remove pointer by pulling it forward. 4. Remove cabinet back by taking out three screws and two clips. Note: Cabinet back has a power cord interlock which is auto matically disconnected when back is removed. 5. Take out two chassis mounting screws at bottom of cabi

3、net. Chassis may now be readily removed by sliding it out of cabinet. 6. When replacing cabinet back be sure that it is parallel to loop and power cord interlock plug fits into socket on chassis. TERMINAL D IS LOCATED Va turn from TERMINAL C S3 S4 SI2 *6 SI4 FM OSC. COIL 508225 SECTION 1 FRONT VIEW

4、SECTION 1 REAR VIEW AM OSC. COIL S07939 FM R.F. COIL S08224 BAND SWITCH 508231 Lettered terminals in Illustrations correspond to similarly lettered terminals on the circuit diagram. 1S7 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19S0 MOST-OFTEN-NEEDED RADIO DIAGRAMS Stewart-Warner Model 9151-A, Continued BRO

5、ADCAST BANDAMALIGNMENT PROCEDURE 1. If alignment of both AM and FM channels are required, it is advis able ta align the AM channel first; then align the FM channel as instructed an Page IS9. 2. Remove chassis and laap antenna (which is mounted ta chassis) fram cabinet by fallowing procedure outlined

6、 an Page 1ST Allow laap ta remain attached ta chassis. 3. In order ta provide a coupling far signal generator during R.F. alignment as instructed in chart below, wind several turns af wire in a circular shape sa that it may be placed adjacent and parallel ta the laap. 4. Connect an output meter acro

7、ss the speaker voice cail ar fram the plate of the 50B5 tube to chassis through a 0.1 Mfd. condenser. 5. Set band switch ta the AM (counter-clockwise) position. 6. Set volume control at maximum and use a weak signal fram the signal generator. 7. Since the dial scale is a part af the cabinet, when co

8、mpletely as sembled, it becomes necessary ta provide a temporary means af locating the dial ta obtain colibratian paints. Rotate gang condenser fully counter-clockwise and replace painter sa that it is parallel with base af the chassis. Now, hold dial scale in front af painter in such a position tha

9、t the ends of the indicator point ta the AM and FM markers. While holding the dial scale in this position, rotate tuning sleeve until painter indicates desired frequency. SIGNAL GENERATOR CONNECTIONS CONNECT HIGH SIDE OF SIGNAL GENERATOR TO SIGNAL GENERATOR FREQUENCY Chassis ground. CAUTION: If your

10、 sig- Lug on trimmer #6 nal generator is de- at top af gang (see signed with an AC-DC figure 1 for location type power supply, of trimmer). connect ground lead of signal generator to re ceiver chassis through a .25 Mfd. condenser. Connect directly to coupling turn. See Step 3 m iff* above far instru

11、ction on coupling loap. I lL* Connect directly to coupling turn. See Step 3 above for instruction on coupling loop. RECEIVER DIAL SETTING TRIMMER OR SLUG NUMBER TRIMMER DESCRIPTION TYPE OF ADJUSTMENT Adjust for maximum output. Then repeat adjustment. 1500 KC Tune to 1500 Kc. generator signal. Jfkj i

12、 (12BM) j c BISCRIMINATRR A V C /DISCRIMINATOR ( 7 ) SECONDARY Vi/ 10.7 MC. FIG. 1 Top View of Chassis E3 V.T.V.M. + GROUND TO RECEIVER CHASSIS DISCRIMINATOR/ . PRIMARY (g4; 10.7 MC. VZ/L-J r fm |4)0SC. COIL 88 MC. Nihi Q9 (B) (3) *55 10.7 10.7 455 KC. MC. MC. KC. Bottom View of Chassis FIG. 2 OISCR

13、IMIMTIIII-MC “I “:X SCOPE GND. FIG. 4 FIG. 3 VTVM and Oscilloscope VTVM Connections Connections for for IF Alignment Discriminator Alignment 收音机爱 好者资料库 RadioFans.CN MANUAL OF 19S0 MOST-OFTEN-NEEDED RADIO DIAGRAMS Stewart-Warner Model 9151-A, Continued FREQUENCY MODULATIONFMALIGNMENT PROCEDURE 1. If

14、alignment af both AM and FM channels are required it is advisable to align the AM channel first as instructed in chart on Page 5 Adjust these trimmers for maximum meter reading the output condenser. CAUTION: If your signal generator is designed with an Not used. Not used. does not affect the signal.

15、 #9-10 2nd IF voltage will be of neg ative polarity. AC-DC type power supply, connect ground lead of sig nal generator to re- ceiver chassis through a .25 Mfd. condenser. Note that as slug #7 is #1112 1st IF rotated, a point will be found where the volt meter will swing rather sharply from a positiv

16、e to a negative reading or vice versa. The cor rect setting is obtained when the meter reads zero as the slug is moved thru this point. Same as above. Same as above. Not used. Connect VTVM as shown fig- * Not used. Same as above. #7 Discriminator, secondary Same as above. Attenuate Connect high side

17、 ! to lug on trimmer #13 (see Fig. 1 for location of trim mer) using a .01 Mfd. condenser in series with gener ator lead. Connect ground lead to the receiver chassis in vicinity of gang i condenser. CAUTION: If your signal generotor is : designed with an AC-DC type power supply, connect ground lead

18、erf sig nal generator to re- ceiver chassis through a .25 Mfd. condenser. 10.7 MC Connect as shown in Fig. 4. Set verticol ampli fier of scope for maximum amplifi cation. #7 Discriminator secondary A pattern similar to that shown in Fig. 5 , should appear on the oscilloscope screen. Check for symmet

19、ry about the 10.7 Me. cen ter point and linearity of the slope. 10.7 MC. above. signal to prevent overload and distortion of response curve. Sweeping 300 Kc. Not used. Synchronize oscillo scope with sweep generator by con necting horizontal input terminals of scope to source of horizontal sweep modu

20、lating voltage on the sweep gen erator. above. FIG. sy If the characteristic is not shaped properly, attempt to obtain sym metry by changing the setting of slug #7. Should that fail to pro duce the desired re sults, then a slight re adjustment of slugs #8, 9, 10, 11 and 12 should be undertaken. Conn

21、ect high side in series with a 270 ohm carbon resistor to FM ANT. ter minal at rear of chassis. Connect ground lead to FM GND. terminal. 108 MC. with 108 Me. Connect VTVM See Step / above for instructions on how to obtain this calibration point. #12 FM Oscillator Set trimmer #12 to re ceive 108 Me.

22、signal as 400 cycle AM Modulation. as shown in Fig. 3. indicated by maximum meter reading. Same as above. 108 MC. with 400 cycle AM Modulation. Not used. Same as above. Not used. Tune to 108 Me. generator signal. #13 FM RF Adjust trimmer for maximum meter read ing. Check calibration and tracking of

23、receiver with input signals of 88 and 98 MC. If difference between dial pointer setting and the above mentioned frequencies does not exceed 0.3 MC. and RF circuit is tracking properly then alignment may be considered satisfactory and no further adjustment is necessory. Where the calibration error is

24、 greater than 0.3 MC. it is advisable to make the following adjustments; Tune receiver to an 88 MC. signal and note whether dial pointer is above or below correct calibration point. Then tune receiver so that dial pointer is at the 88 MC. position. If generator signal was previously received at a se

25、tting above 88 MC., it will be necessary to slightly spread the windings of the FM oscillator coil (#T4 in Fig. 2) so that signal will now be received at the correct dial setting. On the other hand, if generator signol wos received at- a dial setting below 88 MC., then slightly compress the windings

26、 of the oscillator coil until the signal comes in at the correct calibration point. Check calibration at 108 MC. and if it is in error by more thon 0.3 MC., read just setting of trimmer # 12. Repeat calibration adjustment at 88 and 108 MC. until desired accuracy is obtained. Observe dial calibration at 98 MC. If it is found to be incorrect by an appre ciable amount, then make a very slight adjustment in the spacing of the gang condenser plates to receive the 98 MC. signol at the correct dial setting. Then check adjustment of RF trimmer #13 to obtain maximum output 收音机爱 好者资料库 RadioFans.CN