12 Feb
2014
12 Feb
'14
10:18 p.m.
well,
my english could be faulty as well. :-) I think i wrote transistor, to
be replaced with a mosfet type irf840.
In English, the term 'transistor' can mean a MOSFET, a JFET or a bipolar
transistor.
My comment was that in a PSU of this age, my first guess would be that
the chopper transistor was a bipolar transsitor, not a MOSFET. But that
is jsut a guess, I wondered if you had any reason to think it was a MOSFET.
But I took the plunge and substituted the broken transistor with a
mosfet. it kinda works. I had to change the gate resistor as weel (was
In whuich case it's almost certainl the right sort of part. My
experience suggests that SMPSUs fail for may more trivial reasons than
having a MOSFET fitted in palce ofr a bipolar transistor.
-tony