Stromberg-Carlson-Co-1121 电路原理图.pdf

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1、(OWOOll 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1947 MOST-OFTEN-NEEDED (ADIO DIAGRAMS STROMBERG-CARLSON Model 1121 (Coatlnued) Always align using the smallest possible input from the signal generator. A strong signal makes adjustments approximate. Always have volume full on. The required equipment is: 1 E

2、lectronic Voltmeter, 1 Out put Meter, 1 Standard Signal Generator, 1 High Fre quency Signal Generator, 1 No. 80777 Aligning Tool. Aligning Procedure (follow this order exactly) Intermediate Frequency Adjustments Amplitude Modulation The I.F. aligners that are used to adjust the amplitude modulation

3、(AM) channel are found on the top side of the chassis. They consist of 6 adjustable iron cores used to tune the inductance of the 1st, 2nd & 3rd I.F. transformers (161202, 161200, 161201). These cores are found in side the plastic tubes protruding from the top of the I.F. transformers and are equipp

4、ed with small screwdriver slots. 1. Connect the signal generator to the modulator grid, terminal number 8 of the 6SB7 converter tube which is connected to the wave band switch, and is identified by a blue dot. 2. Connect the output meter across the voice coil of the speaker (green and block wires fr

5、om cable). 3. Adjust the signal generator to 455 KC. Use 30% mod ulation at 400 cycles. 4. Adjust volume control full on. 5. Adjust tone control to maximum high (counter clock wise). 6. Adjust range switch to standard broadcast band, (second position clockwise.) 7. Adjust the tuning selector to appr

6、oximately 600 KC. 8. Adjust I.F. cores for maximum output with a reduced signal Input. Frequency Modulation The I.F. Aligners may be found from the underside of the chassis. The adjusters are 6 Iron cores used to tune the inductance of the high frequency coils. 1. Connect the signal generator to the

7、 modulator grid, terminal number 8 of the 6SB7 converter tube, which is connected to the wave band switch, and is identified by a blue dot. 2. Connect the electronic voltmeter to the junction of the 22,000 and the 4,700 ohm resistors in the limiter grid circuit, identified by a green dot. 3. Adjust

8、the voltmeter to the lowest negative voltage scale. 4. Turn the range switch to the 2nd F.M. band (fourth position clockwise). 5. Adjust the tuning selector to approximately 21 on this band. 6. Adjust the signal generator to 10.7 megacycles. No modulation is required. 7. Adjust the cores for maximum

9、 output of the voltmeter. Reduce the input signal and readjust until the max imum output is secured for minimum input. Discriminator Alignment (FM) 1. Connect the signal generator to the grid of the second I.F. tube, terminal No. 4 of the 6SH7. 2. Connect the electronic voltmeter to the center of th

10、e diode load resistors at the point indicated by the orange dot. 3. Adjust the primary for maximum output with the signal generator set at 10.7 megacycles. 4. Switch the electronic voltmeter to the high side of the diode load resistors, identified by a red dot. 5. Adjust the secondary for zero outpu

11、t. 6. Swing generator to 75 KC higher and 75 KC lower in frequency and note the plus and minus voltage. If these voltage values are not approximately equal, repeat operations 3, 4 and 5. Dial Pointer Adjustment Check dial pointer to see that it is aligned through the center of the 2 in the number 20

12、1 of FM Band (1) when the variable capacitor plotes are completely engaged. R.F. Adjustment Amplitude Modulation The Broadcast band should he adjusted first. The built-in loop should remain connected to the antenna and ground terminals. 1. Connect the signal generator to the antenna terminol, using

13、a 200 mmf. capacitor. Use 30% modulation at 400 cycles. 2. Adjust the signal generator to 1500 KC. 3. Adjust station selector to 1500 KC. 4. Adjust range switch to AM Broodcast. (Second po sition clockwise.) 5. Adjust the oscillator, R.F. and antenna trimmer for maximum output. 6. Reduce the input s

14、ignal and readjust the trimmers until the maximum output is secured for minimum input. 7. Adjust station selector to 600 KC. 8. Set signal generator to 600 KC. 9. Adjust iron cores in oscillator, R.F. and antenna coils for maximum output. 10. Repeat 1500 KC and 600 KC alignments until no further cha

15、nge is required. R.F. Adjustment Short Wave The built-in loop should remain connected to the antenna and ground terminals. 1. Connect the signal generator to the antenna and ground terminals of the receiver using a 400 ohm resistor. 2. Set the dial pointer to 9.5 megacycles. 3. Adjust signal generat

16、or to 9.5 megacycles. 4. Adjust range switch to Short Wave (first position clockwise). 5. Adjust oscillator, R.F., and antenna trimmer for max imum output. (No further alignment is required on this band.) 收音机爱 好者资料库 RadioFans.CN MANUAL OF 1947 MOST-OFTEN-NEEDED RADIO DIAGRAMS I 6H6 DISCR. -0.4 V- 57

17、V.AjC. -3V. 0 -04 V. T.-2V. DOT mt KC. I OISCR. 9 9 K).7MC. LOOKING AT INSIDE BOTTOM OF CHASSIS FOR SERIES loANOIlONLY 6SH7 LIMITER 6SB7 MOD.,OSC. 5U46 RECTIFIER 0 -0.ZVt.-0.8V AMai OCT OEMOO. -1 ItT. AUDIO I PM. *e. jLHKUER -0.72V 1 0 0 l0.7Mft 1 I -0.42VJ f0 y_I 6SH7 2nd. I.F. 6V66T OUTPUT Strontb

18、osg Carlseii Modal 1121 R.F. Adjustments Frequency Modulation Align the FM (2) Band first. 1. Set the dial pointer to 61. 2. Connect the signal generator to FM dipole terminals using 39 ohm resistors as indicated. (Disconnect dipole antenna.) Connect Signal Generator ground to chassis ground. 4. Adj

19、ust range switch to FM (2) (fourth position clock wise). 5. Connect the electronic voltmeter to the junction of the 22,000 and 4,700 ohm resistors in the limiter grid circuit, (identified by green dot.) 6. Adjust oscillator R.F. and antenna trimmers for max imum output on electronic voltmeter. FM (1

20、) Band Adjust the same as the FM (2) band using 100.1 mega cycles, setting the dial pointer to 261. Connect the generator to the dipole input using 39 ohm resistors as indicated. Connect Signal Generotor ground to chassis ground. Note reversed Signal Generator connection. 0 0 0 0 A LP 6 SIGNAL GEN. 收音机爱 好者资料库 RadioFans.CN