"Don" none@given wrote in message
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Arfa Daily wrote:
"Don" none@given wrote in message
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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).

If it uses a 3842 / FET circuit, then it just abiut *must* have a startup
resistor and supply pin decoupling cap somewhere, otherwise, how does it
get a supply to the IC to start it up ?

Trust me, I can eyeball a 1.5" length of foil with 5 holes in it! :

As I said in a previous post, only two R's larger than 1/10W:
one as the current sense R; the other as the snubber (it's REALLY
easy to see an RC-D across the primary ... you don't even have to
look hard! : )

If it's ticking, my money is still on a cap ...

My first guess would be the current sense resistor being open
and immediately shutting the controller down. But, I haven't
yet traced the foils to see what else is going on.

Did you get to the bottom of it yet, Don ? I'm always interested in SMPS
faults as I do a lot of work with them, and any info that saves a few
minutes, is extra money in the bank ...

Arfa