"Mark D. Zacharias" wrote in message
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"Smitty Two" wrote in message
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In article .com,
"rv31rv" wrote:

OK, so I search for Yamaha tuner problems (intermittent FM) & find the
threads for LC7210 problems. I replace the IC for $21.50 & same
problem! Tuner works for long periods (hours) & suddenly the signal
strength drops to "0" & white noise only, no FM stations. AM & all
else still work. I leave the unit on & it just as suddenly starts
begins working again. This is really a great receiver & want to fix
it. So: Does any one have a Schematic and any suggestions from the
experts?
Thanx - Bob

Get some very strong reading glasses *and* (NOT "or"!) a very powerful
magnifier, along with the brightest light you can find, and look for one
tiny little cracked solder joint. It might be so tiny that you won't be
able to see it even then, unless you wiggle the components one at a time.

Then get some liquid flux, and reflow that joint. Don't even think about
skipping the liquid flux. You *need* it.

(I'm not an expert, but I play one on usenet.)

More specifically, the front-end pack may need resoldering. Better if a
professional does it, but liquid flux is NOT needed. 60/40 solder
(rosin-core ONLY) contains flux already.

Mark Z.

Last time I had a problem very similar to this, although not on a Yammy
specifically, it was the 10.7 MHz filter that was internally intermittent.
When it was wrong, you could get it back by sharply rapping the filter case
with a screwdriver tip. Just as you say, it would go ok for hours, and come
and go on its own.

Arfa