RFC15 supplies the 5V to the VDD pin of the MC14570... how can there be
4.23V at the pin if RFC15 is open and there is no other VDD pin on the IC?
I'll answer my own question: apparently, very easily.
Power-off DC resistance check confirmed that the RFC15 was open. No visual
indication of
any problem with it when examined. I had a larger, green version of the
100uH left
over from another mod, so I replaced it and low-and-behold, no warble.
Someone
mentioned to me that later versions of the K2 have the sturdier part -- I
hope so.
The MC14570 must have been getting DC from the inputs in lieu of no DC at
VDD, hence
the near-5V reading.
A ham and builder for 25+ years, and worked in semiconductor manufacturing
for 10+ years,
and still things to learn.
Thanks all for the help. Can I have some catsup for my crow, please?
Bill
W1PA
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