{Collins} HF-380 Lowpass Filter Fixed - New Problem- only some freq Xmt



I know many of you will tell me to just send the radio into one of the
experts. and that I am the radios worst enemy BUT I really enjoy learning by
trying to fix these issues myself with the support of the experts on the
Reflector (like Jim, WA9Z) and others.   

 

My no Rx-Tx was due to a bad trace on a 14v bus on the A2A2 LowPass filter
card.    Fixing this brought back my Rx and Tx 100% on all frequencies.  I
have had a problem for some time with a audio beep/cruch sound whenever the
radio was tuned across a 1MHz boundary.  I was advised that it was a
temporary loss of lock on the Synthesizer VFO and that exercising the VCO
trimmer caps (2) just a hair each way would likely correc the problem.
Unfortunately it did not.

 

Now Rx works perfectly and spot on correct frequencies (WWV, comparisons
with my Flex 6700) but I started having problems where on some frequencies
where with CW, power would be 90W peak  for split second and then disappear.
After repeating this  I figure one of the ALC protection circuits are
kicking.  I recheckedc the Low pass filter and the relays seem to be correct
for the frequency selected.

 

Anything in the Synthesizer (or Oscillator that needed to be moved around)
that could have caused this?  I hate to believe in coincidences.

 

73 Jerry NY2KW

 




This archive was generated by a fusion of Pipermail (Mailman edition) and MHonArc.