i have been over the solder joints numerous times
and am convinced they are good
unsoldered and re-soldered all questionable ones
seems to be more of a problem with use
such as a component heats up and fails
thanks for any advice
don

Have you checked the power supply voltage(s)?

Bad electrolytic caps can cause all sorts of havoc. They aren't necessarily
bad in a way that's easy to measure. High impedance, leaky, low value..