[Hammarlund] HQ-129-X Power Supply Problem

[Richard Knoppow]

      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.


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