[Hammarlund] HQ-129-X Power Supply Problem

[Kenneth G. Gordon]

On 31 Jan 2014 at 12:26, Richard Knoppow wrote:

>       I just replaced the filter caps in a HQ-129-X. I 
> thought I would pass along the symptoms that the old one 
> caused. One section went open. The original symptom that 
> drew my attention was spurious responses all over.  I had 
> the same thing with an SP-600-JX.  You would not think a 
> filter cap could cause this but it can and does. There was 
> also excessive hum but I heard this only on phones.  The 
> SP-600-JX hum was about normal curiously enough.
>       The first replacement can I tried on the HQ-129-X 
> seemed OK at first but the audio was very low level and 
> bassy. Curious.  So, since the only thing changed was the 
> cap I removed it and measured it. One section, supposed to 
> be 20uf measured about 2uf.  Replacing the can with 
> individual caps cured all the problems. I will get a good 
> replacement for the can.
>       The point is that some symptoms that bad filter caps 
> can cause are not too obvious.

Very interesting. Thanks.

Ken W7EKB