On 14 Juni, 19:48, Jeff Liebermann wrote:
On Mon, 14 Jun 2010 10:15:57 -0700 (PDT), powerampfreak

wrote:
The powersupply input has no MOV.

It's usually on the fuse holder or input filter. *The idea is that the
MOV should be the first device the power sees after the fuse, but
before any circuitry. *For power supplies with AC connectors mounted
on the PCB, the MOV will of course be mounted on the PCB.

I thought this from the begining
until I realized it was a inrush limiter NTC.
Actually, if looking very close to the NTC body, there are a small
small mark in the middle, but not a hole.
If this was the source of flame I would suspect more evidence.

It's probably not the NTC thermistor. *It looks very much like an MOV,
but goes between the input bridge and the input DC filter caps.
http://www.gesensing.com/downloads/datasheets/920_325a.pdf
If it were smoked, the resistance would be quite high and the scope
would not work. *However, *you might consider scraping the hole with
something sharp to see if it can be enlarged. *If the outer coating on
the TNC themistor collapses into an internal cavity, then there's a
problem.

Got an IR thermometer? *Wave it around the power supply and input
section to see if anything is hot and ready to blow.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558


I actually got in touch with the industrial engineer who operated the
scope when it failed.
He said the scope was NOT under any measurements when the flame came
out of the rear!
It was just standing switched on and suddenly bang and flame......
It sure looks more and more to be the mains filter, though measures
fine.