[ICOM] Ailing IC-745 - any thoughts?

[John Geiger]

Hi Richard,
Sounds like it is going into self oscillation on several frequencies.  As a
first step, open the case, and tighten all circuit board screws.  Self
osciallation can occur when the grounding for the circuit boards is
interruped by loose screws.  I have had the same problem with an Icom 551D,
706, and FT100D, and tightening the circuit board screws fixed it.

Good luck in your attempt, let us know if it works.

73s John AA5JG


(ex: W5TD, NE0P, N0EEN, KA0IFG)
Confirmed 6M addict: 6M WAS #1275, 6m VUCC #1260

----- Original Message ----- 
From: "Richard Peterson" <wb5nen at hotmail.com>
To: <icom at mailman.qth.net>
Sent: Tuesday, June 12, 2007 2:30 PM
Subject: [ICOM] Ailing IC-745 - any thoughts?


> I want to thank the many folks who were kind enough to make
recommendations
> on where to ship my 745, should I elect to do so. Thanks to everyone! It
was
> very, very helpful.
>
> I have taken an initial look at the shop manual, and have thought about
> repairing this on my own, but for right now, I am puzzled.
>
> On 160, 80 and 40 meters, it works perfectly. But on any bands above that,
> and you key the mic, you get full output (just as if you hit the key) on
> some really oddball frequencies. Further, this full output occurs
regardless
> of where the RF level pot is set. Plus, the tuning control makes no
> difference at all. For example, on 14 MHz, the output is fixed at around
24
> MHz. You can spin the knob, but the frequency on my counter does not
change.
>
> This rig has several VCOs, as I recall ... but I am beginning to think
there
> is a logic problem.
>
> Any suggestions?
>
> Richard
> WB5NEN
>
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