[Hammarlund] HQ-110C Help!!!

[Al Parker]

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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