[ale] Pictures of the culprit (was OT: Diagnosing HW problem)

[Richard Atcheson]

On Wednesday 15 June 2005 02:46 pm, Calvin Harrigan wrote:
> Seems like a power transistor (probably a MOSFET) ?for the switch mode
> regulator. Typically used to drop the 3.3 Volts down to the 1.4-2.0
> volts used by most CPUs. ?That circuit is pretty far in from the outside
> world. ?If I had to take a guess two things might have happened, it was
> shorted by a screw or some other piece of metal or the least likely one
> of the capacitors shorted and caused an over current situation. ?Either
> way motherboard is bye-bye. ?Sorry.

Do any of those three caps to the left of the device have  puffed up tops?  
Hard to tell from the pics but seem to be.  Once upon a time there were a BIG 
BUNCH of them, bootleg I think, that caused a lotta headaches.  I've replaced 
about a dozen on some abit mobos.   They have been known to blow and cause 
major damage. 

On one of my mobos there are 5 or 6 things similar to your blown one,  all 
labeled Q-something.  Q is usually used to denote transistors.  My guess is 
they are power transistors used in a regulator circuit.  Obviously the frying 
is caused by over current which could be caused by a bunch of things 
including dust that gets a little wet/damp or simply one of the components 
got old and tired like me and gave it up.
ra