Seems in my younger day what you describe was often caused by a bad cathode
bypass capacitor. Probably there are similar things that could go wrong
today.
73, Mike N4NT
----- Original Message -----
From: "Dr. Gerald N. Johnson" <geraldj@weather.net>
To: <tentec@contesting.com>
Sent: Monday, September 28, 2009 11:20 PM
Subject: Re: [TenTec] Omni 5 Feedback
> On Mon, 2009-09-28 at 15:15 -0400, Howell, D. Haney wrote:
>> My trusty Omni 5 has been under wraps for a few months. When I fired it
>> up
>> recently I experienced motorboating and rumbling feedback though the
>> speaker. As the old hamfest saw goes, it was working fine the last time
>> I
>> used it! Any suggestions where to start troubleshooting?
>>
>> Haney
>> k2xn
>
> Usually motor boating and rumbling feed back are a sign that the power
> supply bypass electrolytics have gone nearly open or have gone way down
> in value. That's not only the main power supply but the various supply
> voltage busses on the board.
>
> But for a first step, to make sure the board grounds are good, tighten
> all the PC board mounting screws. Then in Tentecs wiggle the cable
> connectors. Or pull them off and apply a tiny bit of DeoxIT to each pin.
>
> 73, Jerry, K0CQ
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