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FRONT  END  ALIGNMENT 

FM  FRONT  END  ALIGNMENT  FOR 

FM  SECTION 

1. Connect  RF  generator  to  the  antenna  terminals  with  the  following

adaptations:

FROM 

GEN. 

270Jt 

.__ .... ....._ _____ ► 

TO 

GND. 

2. Set  RF  generator  and  FM  tuning  dial  to  92  mHz.  Generator  output  should

be  about  6  uv.  Peak  1205,  1204  and  1201  for  maximum  audio  output.

3. Set  generator  and  FM  tuning  dial  to  106  mHz.  Peak  RF  trimmer  and  mixer

trimmer.

4. With  about  3  uv  from  FM  generator,  repeat  procedure  until  no  further

output  is  obtained.  Signal  should  look  like  this:

5. The  only  time  that  the  oscillator  mixer  and  trimmer  should  be  touched  is

if  the  calibration  is  out  of  specification.

Summary of Contents for 631 Receiver

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Page 2: ...sitions High Level Inputs Input Impedance Signal for Rated Output S N Ratio Frequency Response in Flat Position Treble Controls Measured at 10 000Hz Boost Cut Bass Controls Measured at 30Hz Boost Cut...

Page 3: ...ith bias pots lK still full ccw from top of unit check supply for 48 to 50 Adjust bias pots for 0 8 mA current from each test point in the rear of the unit to ground 2 Check power supply board Check p...

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Page 8: ...rimmer to 1600 kHz Tune RF trimmer at 1400 KHz and antenna slug at 800 KHz Seal antenna core 6 Repeat Step 5 until unit is aligned and max output at given frequencies has been achieved Calibrate 590 K...

Page 9: ...2 mHz Generator output should be about 6 uv Peak 1205 1204 and 1201 for maximum audio output 3 Set generator and FM tuning dial to 106 mHz Peak RF trimmer and mixer trimmer 4 With about 3 uv from FM g...

Page 10: ...TE_R __ b Q2 01 GNC DRIVE J t I LOW FN I RF HlGH AM 300 R GNO FM 68 METER DRIYE IF OUT R602 33K 10 7 MHz MIX HIGH MIX LOW OSC HIGI I OSC LOW Z FM 15 __ __ FRONT END AGC IF C e 12v Q202 4 9 FRONT END B...

Page 11: ...70 7 1 2VDC T303 r f C312 470 t T 104 R311 R316 150K 3K Wv 8 9 t 2VDC L JUMPER ALL VOLTAGES POSITIVE DC 15 MEASURED WITH 20 K ohm V VOM AND 117 VAC LINE FM VOLTAGES MEASURED WITH 300 OHM LOAD ON EXTEN...

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