[ICOM] IC-745 Repair / Help

[Vladimir Sidorov]

Ed,

You may try to clean up plates of the boards where they are connected to the 
common bus, i.e. the TRX body, just under and around respective screws. As 
time goes, these areas get oxidized and it causes problems similar to what 
you describe.

GL anmd 73,

Vladimir VE3IAE

---


----- Original Message ----- 
From: "Ed" <edanderson1 at verizon.net>
To: <icom at mailman.qth.net>
Sent: Tuesday, January 27, 2009 12:53 PM
Subject: [ICOM] IC-745 Repair / Help


> Hi All:
>
> This is my first post.
>
> I picked up a very nice looking IC-745 at an estate sale this past fall.
>
> When I got the radio home and put it on the bench it didn't work.
>
> The symptoms are no RX/TX, no display, and no response from front panel
> controls.
>
> The light on the S-meter does illuminate, I can vary the RF gain and the
> receive led does go on and off
>
> when I rotate the squelch (SQL) control.
>
> I have no history about this radio.
>
> I replaced the RAM board with a ICOMPROM from PIEXX, but that did not 
> help.
>
> I think the problem lies somewhere on the logic board.
>
> All of the VCC voltages look good.
>
> There is a good clocking signal on the CPU (IC3) pins 30 & 31.
>
> There is no clocking signal on IC2 (CPU input control) pins 18 & 19.
>
> Since this same basic design is used in a number of older ICOM radios, I 
> was
> wondering if anyone might be able to
>
> give me some pointers before I just start guessing at what components 
> might
> be bad.
>
> I have down loaded the service manual, all of the board layouts and 
> circuit
> diagrams.
>
> This would be a good winter project and I would love to bring this radio
> back to life.
>
> Thanks in advance.
>
>
>
> Ed / N1IWV
>
>
>
> Edanderson1 at verizon.net
>
> ----
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