[Hammarlund] HQ-180 can capacitor

[L L bahr]

Bob,

My thoughts are most likely you don't have a bad can cap.  I say that because you say you have the distortion only on CW.  If the can cap was bad I would think you would notice distortion on voice too. (Are you sure you have no distortion on voice?)  That said, it sounds like someone "strapped" an outboard electrolytic across a section of the can cap.  This is bad practice but surely indicates someone was trying to "shore up" a weak can electrolytic. (They do dry out over time.)  If I were you, I would remove the strapped in cap along with the can cap and replace it with a fresh can cap you either rebuild yourself or buy from a dealer selling fresh can caps for your radio such as Hayseed Hamfest.  I would do this even if you had no CW distortion.  (Those original electrolytics were designed with a 6 to 8 year life.)  It's possible this will also repair the CW distortion problem too as the distortion might be more apparent on CW then on phone.

Lee, w0vt    

> 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