I doubt that the SRD is the problem. It's just the last thing in the
chain, and a number of things ahead of it all have to work right first.
I'd look first at any connections and wiring between various sections,
and jiggle things around to see if the symptoms can return. Next, if ICs
and transistors and other parts are in sockets, jiggle them too. For
ICs, it's easy to pry one end out slightly - with power off - then press
it back in, and repeat at the other end if it seems necessary. Re-wiping
the contacts can do wonders sometimes. I don't know if HP ever used the
notorious TI IC sockets, but they are a big cause of problems in Tek
gear. The same for TI brand ICs that have silver plated leads - whether
socketed or soldered in, these can suffer connection failure. This is
well known and discussed a lot over the years.
Sometimes an intermittent can be a short instead of an open, with
various causes, like errant braid strands on coax, wire clippings,
solder gobs, and loose hardware that happen to eventually land in just
the right spot. I have found this generally the second most likely
fault, after open or poor connections. This is also a type that can
happen once, if say a loose item caused the problem, then gets knocked
out of place (sometimes to a different place where it can cause a
different problem later) by moving the unit or opening it up.
The problem in diagnosing an intermittent that came and went only once,
is that you'll never know for sure what caused it, unless it can be
forced to fail again and stay that way for a while, and tracked down.
Or, if you happen to find something rattling around inside that can be
blamed. Short of that, the next best thing is to check and clean up
anything suspicious, and hope that you hit the actual culprit in the
process.
Ed
_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
