Icom IC-551 (IC 551 IC551) transceiver mods reviews software and diagrams

   
 
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05 May 2024, 12:51 UTC 


Transceivers


Motorola

Icom IC-551 (IC 551 IC551)
IC-551
Programming interface schematics for Icom:
Programming software for Icom IC-551 (IC 551 IC551) :
PDF User Manual for Icom IC-551 (IC 551 IC551) :
PDF Service Manual with schematics for Icom IC-551 (IC 551 IC551) :

Mods for Icom IC-551 (IC 551 IC551) :
    Icom IC-551 (IC 551 IC551) Frequency Alignment
    Icom IC-551 (IC 551 IC551) EX-107 VOX UNIT -- Installation
    Icom IC-551 (IC 551 IC551) EX-108 P.B. TUNE UNIT -- Installation

Icom IC-551 (IC 551 IC551) technical specifications :  Icom IC-551 (IC 551 IC551) technical specifications



Icom IC-551 (IC 551 IC551) Frequency Alignmen

  1. Locate R122 near center of main board, directly in front of center mounting screw. The top of this resistor is bare and is used as the test point for the BFO. Connect frequency counter to this point.

  2. Set mode switch to LSB. (Dial frequency unimportant)

  3. Adjust C105 for 9.013000 MHz.

  4. Set mode switch to CW.

  5. Turn on RF power control and set at minimum power output.

  6. Set receive/transmit switch to transmit.

  7. Short CW key jack on rear of radio or close CW key if attached.

  8. Adjust L33 for 9.010500 MHz.

  9. Return to receive.

  10. Set mode switch to USB.

  11. Adjust L32 for 9.010000 MHz.

  12. Set mode switch to CW.

  13. Adjust L31 for 9.009700 MHz.

  14. Remove cover from PLL unit.
    (6 x 17 cm. metal cover on right of main board.)

  15. Locate R44 near rear of PLL unit. The top of this resistor is bare and is used as the test point for the VCO. Connect frequency counter to this point.

  16. Set mode switch to LSB.

  17. Tune dial to 50.101.5 MHz.

  18. Adjust R59 for 41.088500 MHz.

  19. Tune dial to 50.101.4 MHz.

  20. Adjust R60 for 41.008400 Mhz.

    The following steps apply only to units equipped with FM unit EX106.

  21. Dial 50.100.0 MHz.

  22. Adjust L8 in FM unit for 50.100000 MHz on transmit at output to dummy load.