On Sun, 13 Jun 2010 14:16:36 -0700 (PDT) powerampfreak
wrote in Message id:
:

I was given an oscilloscope, a Fluke PM3082 from a retired industrial
electronics engineer.
He said that during a measurement, the oscilloscope's powersupply just
bang and a flame came out of the rear panel. After this, the scope was
left for several years...until I got it.
The mains fuse has really exploded. Shattered glass in the fuse
holder. A brief examination of the primary side of the smps reveals no
shorts. The smps is an ordinary flyback supply. Mains rectifier ok,
switch ok, snubber, line filters all ok. Really don't know why the
mains fuse went.
I just don't want to put a new fuse in and try again, not before I
investigate the cause.
Could an incorrect measurement setup cause the mains fuse to explode?
Anyone familiar with these scopes or perhaps has a service manual for
it?
Best regards
PAF

IF you are sure there's nothing wrong on the primary, check for shorted
diodes and caps on the secondary side of the switching transformer. You
mention that you checked the "switch". Do you mean the power transistor(s)
that drives the primary side of the switching transformer?

As Jeff said, isolate the power supply from the rest of the scope if
possible. You should be able to use a lower rated fuse at this point to
help minimize any damage if you don't have any way to current limit the AC
input.

http://www.jetecnet.com/ claims to have a service manual for $10.

Might also want to search for free manuals for PM3084, PM3092, or PM3094.
They may share the same power supply.