[Hammarlund] HQ-110C Help!!!

[Mike Lopez]

Thanks Al, could be a microphonic tube or cap, but it doesn't really sound 
like that. I can get it to a threshold of squealing and tap all over it and 
it doesn't change. I'll let you know if and when I figure this thing out !!

Mike

----- Original Message ----- 
From: "Al Parker" <anchor at ec.rr.com>
To: "Mike Lopez" <n8azc at sssnet.com>; <hammarlund at mailman.qth.net>
Sent: Friday, December 19, 2008 5:13 PM
Subject: Re: [Hammarlund] HQ-110C Help!!!


> Hi Mike,
>    I'm chasing a microphonic induced similar oscillation in an HQ-180 
> right this moment.  Tap around the tubes (very lightly) with a plastic 
> wand to try to figure out just what's the main source.  Right now I think 
> mine is originating at the HF osc., 6C4, but not positive just what 
> component it is. I just came looking for the missing schematic, but will 
> probably stick a new tube in there to see if that might be it.  I've seen 
> microphonic capacitors before, and the area of 2 caps under the osc.sfmr 
> on the high band seems to be very sensitive to a very light tap.
>    Hope this is some help.
> 73,
> Al, W8UT
> New Bern, NC
> www.boatanchors.org
> www.hammarlund.info
>
> "there is nothing -absolutely nothing- half as much worth doing as simply 
> messing about in boats."
>   Ratty, to Mole
>
>
> ----- Original Message ----- 
> From: "Mike Lopez" <n8azc at sssnet.com>
> To: <hammarlund at mailman.qth.net>
> Sent: Friday, December 19, 2008 4:49 PM
> Subject: [Hammarlund] HQ-110C Help!!!
>
>
> I have an HQ-110C with a weird problem that is driving me nuts!  When I 
> switch to the SSB/CW mode, the radio goes in to continuous audio 
> oscillation.....it screams. I have the AVC in the off position ( actually 
> it doesn't make any difference, on, or off). I can stop the scream at -0- 
> volume and bring it on at just below the 8 O'clock position ( I can barely 
> open the volume control ). I can remove all of the tubes (except the 2 
> Audio tubes of course) and it still does it. I can the see the oscillation 
> pretty much everywhere on the scope. It's not a humm, its like 1-2K 
> cycles. The radio works in the AM mode and actually still works at minimum 
> volume in SSB mode. I can hear a beat note at low volume when tuned to an 
> AM signal so the BFO is working. I cleaned all the switches ...the problem 
> doesn't seem to be there. Any clues????
>
> Thanks,
> Mike N8AZC
>
>
> --------------------------------------------------------------------------------
>
>
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