w2agn <[EMAIL PROTECTED]> made an utterance to the qrplist gang
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I'm not sure how many on this list are building an NC2030, for for what
it's worth, here is an interesting experience.
I have been building a section at a time, doing all the necessary
tests, which it has passed. I finally got to the final receiver test,
and was overjoyed to hear the sweet sound of the rushing noise in the
headphones. As I sat patting myself on the back, there was a crackling
in the headphones...then silence.
A check showed that now the 3v regulated line was 1v! Obviously a short
somewhere. So I spent hours with magnifying glass looking for a screwup.
I couldn't find it. So I resorted to the extreme measure of cutting the
3v bus in a couple places to isolate the problem. It showed up to be in
the IC5 circuit, but still, I couldn't find a short. The 3v line is
bypassed here with a .1mf chip capacitor. They NEVER short, right?
WRONG! I removed the cap and it measured 3 ohms. I replaced the cap,
soldered across the traces I had cut in troubleshooting..and all works
FB again. (No, there was no solder bridge or piece of wire, the clean
capacitor, out of the circuit, was shorted).
It is not always the simplest thing that goes wrong, or as Sherlock
Holmes so eloquently put it, "When you have eliminated the impossible,
whatever remains, however improbable, must be the truth."
--
_ _ _ _ _
/ \ / \ / \ / \ / \ John L. Sielke
( W )( 2 )( A )( G )( N ) http://w2agn.net
\_/ \_/ \_/ \_/ \_/
"CRUSTY OLD CURMUDGEON, AND PROUD OF IT"
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