[Hammarlund] HQ-180 can capacitor

[Richard Knoppow]

----- Original Message ----- 
From: "Robert Sauvan" <rsauvan at beyondbb.com>
To: "Hammarlund Mail List" <hammarlund at mailman.qth.net>
Sent: Friday, November 28, 2014 6:09 AM
Subject: [Hammarlund] HQ-180 can capacitor


> Hi all,
> I had been working on my HQ-180 replacing this and that 
> and doing a complete alignment. It works fine (better than 
> ever) but I still feel I have distorted cw signals 
> somewhat. I had posted this previously and most pointed to 
> the AVC section of the circuits but I have not located 
> anything amiss there.  I am curious to know whether or not 
> the possibility of one of the caps in my can capacitor 
> might be causing the issue. I always noticed that there 
> was a large electrolytic mounted under the chassis that I 
> thought looked a bit out of place. After digging into it a 
> bit more, It became obvious it was replacing one of the 
> can capacitors. So, this got me to thinking that maybe the 
> can cap is starting to slowly fail and therefore possibly 
> this is my issue with the distorted cw signals. SSB 
> signals sound good. I have made a bunch of resistance and 
> voltage measurements (except at this can cap area) but 
> have not found a spot that is looking really bad. So, any 
> ideas?
>
> Thanks-Bob-W0YBS

     The quickest way to check a cap is to replace it. Don't 
bridge another across it because if its leaky that will make 
no difference.
     Bad filter caps cause all sorts of problems without 
necessarily increasing hum a lot. For instance, one of my 
SP-600s began to have very bad spurious signals, this turned 
out to be one of the filter caps. Also check any cap 
associated with the AVC, the bypass caps must have good 
performance because AVC circuits are usuall rather high 
impedance so it doesn't take much leakage to upset them.
     Its likely Hayseed Hamfest has direct replacements for 
the original can cap.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com