BigTom said:
is there a quick way(in circuit)to test mosfets.
bud2508 and irf9620 in particular.
BU2508 (not BUD2508) is a normal bipolar (non-FET) HOT, IRF9620 is a FET
mostly used as a series regulator (in TV sets and monitors) or as a load
capacitance switch (in monitors). Generally, test them using the diode
test of your multimeter. The HOT will measure as 2 separate diodes B-E
and B-C, sometimes the B-E reading will give you 50mV. The FET will
measure open all ways, except maybe for the protection diode between D
and S. For hints on your repair, you need to give more context so that
people can be of help.