[Premium-Rx] Mackay question

[Robert Nickels]

I guess these receivers hover just below the "premium" threshold, but if 
anyone would have experience with them, it's probably someone here!

I have two ITT Mackay synthesized general coverage receivers, a model 
3020A and a 3021A, the only difference being the tuning method (dial vs 
thumbwheel-type switches).   Both have the same problem and I've been 
unable to nail down the source.   The problem is on USB or LSB mode (or 
presumably on CW, although I haven't tried) - the audio will develop a 
low-rate "gurgling" sound after a while (it sounds like bad AC 
modulation).   Usually the audio is fine after power-on, but develops 
soon thereafter.  I suspect this is due to some kind of ripple or 
component-aging in the PLL but would be interested in any suggestions.
Thanks and 73,
Bob W9RAN

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