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General Category => Radio Reviews, Questions and Comments. => Topic started by: nofake on June 04, 2020, 02:25:51 PM

Title: service manual icom-251E and wire diagram mutek board
Post by: nofake on June 04, 2020, 02:25:51 PM
Hello,

I am looking for the service manual for the Icom ic251E and the wire diagram for the mutek frontend board.
I had a problem with the mutek board and took it out without making pictures or schematic of the wires, and now i have nothing on the recieving end.
Can anyone help me with this problem.

73
ON3TVA
Title: Re: service manual icom-251E and wire diagram mutek board
Post by: Sparks on June 04, 2020, 10:10:23 PM
Quote from: nofake on June 04, 2020, 02:25:51 PMI am looking for the service manual for the Icom ic251E and the wire diagram for the mutek frontend board.

1. Free download here (PDF): https://www.manualslib.com/products/Icom-Ic-251e-3963801.html

2. Check pages 12-19 in this PDF about "ICOM IC-251E + MUTEK BOARD":
https://worldradiohistory.com/UK/Amateur-Radio/Amateur-Radio-1983-07.pdf

I didn't succeed in finding the Mutek circuit diagram for you. I found these phrases at more than one site, probably what you didn't do?:

Quote from: undefined(1) FRONT PANEL

  • Remove four retaining screws and top cover.
  • Remove four retaining screws and bottom cover, disconnecting the speaker.
  • If you have a Mutek front end board fitted remove it now. MAKE NOTE OF THE CONNECTIONS TO IT! ***WRITE IT DOWN***
  • Remove the four front panel frame screws
  • disconnect the wiriing harness and remove the front panel. NOTE WHERE ALL THE PLUGS GO! ***WRITE IT DOWN***
  • Locate the orange wire linking the mode switch and the board behind the power control potentiometer.
  • Desolder it from it's present position on the mode switch and move it to the common side of the switch. That completes the front panel mod.
This example from: http://www.pa7es.nl/All_ICOM_mods.pdf

Put this exact search phrase (with quotation marks) into Google:
"If you have a Mutek front end board fitted remove it now"
Check the hits, even the picture hits, maybe something there will yield what you need. Good luck!
Title: Re: service manual icom-251E and wire diagram mutek board
Post by: gil on June 07, 2020, 04:55:50 PM
Hello,

Mine is starting to act up a bit, with a few-second delay befopre starting... Probably a capacitor going bad...

Gil.