"William Sommerwerck" wrote in message
. ..
The problem with bad solder joints and cracked traces is that they are
often
difficult-to-impossible to see.

We recently had a similar problem that was traced (joke intended) to a
cracked trace under an IC.

I would start systematically unsoldering and resoldering every joint on
the
board. It's not enough to melt the solder and push it around. You need to
suck or wick it off, then apply fresh solder, preferably eutectic (63/37).


How does your company make a living dealing with such dry joint problems by
sucking or wicking every joint before resoldering ? Just interested, as I
sure wouldn't be able to spare the time to approach it like that, and still
keep it financially viable. For sure I agree that just reflowing the joints
is not really enough, but I don't think that I know anyone else in the trade
who deals with bad joints in any way other than just reflowing with a touch
of new solder added, whether they are reworking an obvious bad joint, or
carrying out a 'blanket solder-up' job of an area that has an invisible bad
joint.

I do sometimes clean old solder right off, but only when there are obvious
signs that the chemical composition of the joint has deteriorated beyond
recovery - for instance where a joint has gone crystalline as a result of
being subjected to continuous heat-stress from the component that it is
connecting.

To the OP. I have had a number of problems with bad connectors on Denon AV
amps. Just because the connectors 'look' good, I wouldn't immediately
dismiss them as being blameless. It would be worth squirting some switch
cleaner in, and then 'working' the connector in and out a few times. Also,
if you have the facilities / expertise, its worth reworking the joints on
the surface mount DSP ICs

Arfa