Re: Surface mount component in receiver likely to fail/respond to being hit?


"N Cook" <diverse8@xxxxxxxxx> wrote in message
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TwoBearCatz <twobearcatz@xxxxxxxxx> wrote in message
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OK, This is a long shot and I'm not an electronics expert by any means
but here goes.

I've got an older NAD surround receiver that has started to break
down. Basically it seems the left front channel in particular was
giving out. Strangely enough, I found through another post on the
Internet that you can temporarily fix this by banging the receiver on
the one side. Naturally, I thought bad connection but after taking the
cover off I can't see any bad connections.

However, I *think* I have narrowed the problem down to one board with
a few surface mount components. It seems that when I tap it with a
screwdriver it affects the sound. In particular there is a crystal of
some sort on this board along with some IC's and other components.
Again, I don't see any bad solder joints.

Is there any component that is likely to break in this way? I was
thinking maybe the crystal, but I have no idea. I can put up pictures
of the board if it help. TIA for any help!


It is a recurring problem in radios for silver migration around the edges
of
the ceramic plates in 3/5/6 pin ceramic resonators to cause problems and
also people banging xtals with screwdrivers ;-)



Also the board connectors - particularly if it is a mother / daughter board
scenario. Ifyou have really pinned it down to that board using a fist,
hammer and chisel, you should now be able to refine the search down to a
specific area, and then component, using a combination of heat, cold, and
the *** end of a Biro pen ... d;~}

Any SM components can get / have bad joints on them, but you often need
something with a bit more optical gain than a Mk I eyeball, to spot them.

Arfa


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