> On my biostar P35D2-a7 Motherboard 2 FET type (On Semi) 58N02G (
> http://www.chipdocs.com/datasheets/datasheet-pdf/ON-Semiconductor/NTD85N0=
2.html)
> blew, apparently the first one evaporated its drain leg, and the second b=
aked to
> death. I recall looking at the screen and the computer appeared to be sti=
ll
> running when we noticed the smell and turned it off! I wonder what might =
cause
> this type of failure, and whats the probability that just replacing these
> transistors could fix the problem? There is also a third different FET in=
 that
> group http://www.alldatasheet.com/view.jsp?Searchword=3DFDD8780 which loo=
ks
> unharmed. I can see no nearby controller or gate driver!
> =

> Also if I can find compatible transistors, any tips on how to solder these
> type of tightly spaced SMD components?
> =


Take a look at nearby electrolytic capacitors. If they are bulging on the t=
op =

their capacitance is much lower than it should be.

I had the same fault on one motherboard. I replaced all capacitors (almost =
all =

where bulging) and the FET (which I had the luck to be able to salvage from =

another mobo). Then it wortked a couple of years more.

See also this link:

<http://en.wikipedia.org/wiki/Capacitor_plague>

/Ruben

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124, 200 39 Malm=F6, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D

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