Mike wrote:
ok question. we may have to step up a notch now.

What kind of SMPS controller does it have? is the controller and chopper
transistor seperate, or is it an all-in-one such as a VIPIR or STR
regulator. those are notorious for dying out.

3842 driving a discrete FET (can't see the P/N on the FET since it
is hiding behind the input filter).

And, to answer "Bob's" questions, below (his post hasn't made it
to my news server):
- first thing I did was reflow all the solder joints (since it is
so easy to do and I've seen problems with fatigue in the past)
- there are only two "higher current" (wattage) resistors on
the board: one in the snubber and the other in the current
sense leg. The current sense R was verified as "approximately
the right value"; the snubber was ignored.

I made a photocopy of the foil patterns last night and will trace
it out this evening if I have time. In the late evening quiet, I
also was able to notice a "ticking" sound -- as if the switcher
was starting up and then shutting down again. I'll pay closer
attention to the current sense circuit when I am tracing the
foil patterns tonight -- along with the OVP shutdown (as those
are the two things that come to mind that could cause this
cyclic start-shutdown behaviour).

But, tomorrow brings another surplus equipment auction so I
may stumble on a suitable replacement and just pitch this... :-/

"Bob Urz" wrote in message

I assume you checked ALL solder connections for bad joints?
And put your meter on all higher current film resistors and compared the
measured value to the color code?

Bob