{Collins} KWM-2 Idle Current Changes with Tuning - RESOLVED



Thanks to the many people who offered constructive guidance on resolving this issue!  

After following up on your suggestions and confirming many parameters, the issue was finally resolved by changing the balanced modulator diodes with new Schottky diodes and then balancing the carrier again. 

It was necessary in the past two months to do some work in the area of the balanced modulator when two of the glass diodes unexpectedly cracked.   I replaced them with two germanium diodes I had on hand, and getting excellent audio and signal reports, I assumed all was well.  But apparently this mismatch also caused the idle current to change with tuning.  

I realize that this behavior might be aided by another problem yet to be discovered.  but for now, the idle current is stable. 

I must add that even now, the carrier balance is still not perfect.  I will be working on extending the range of carrier adjustment but even in this condition, the idle current is now stable while tuning the PTO, Exciter, or PA Tuning after replacing the balanced modulator diode ring.

I hope this information will help others in the future.

73, Mike
KD9CNV




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