LanWay PCs failing

[mikeprice]

OK - not a make I recognised when I got here but there a quite a few of them - probably 5 or more years old

BUT they aren't the oldest here but every major failure of a PC in the last 2 years has been one of these

 

 

Symptons are normally graphics related - screen suddenly goes some variety of stripes - and PC locks

 

I have just (I think) got one working by adding a second video card and another seeme to be working fine the same way - but others just won't start at all - no clues, beeps or anything - either via onboard video or PCI video

 

Oh - except keyboard lights flash once

 

I have tested the hard drives - all fine - and some are working fine in other PCs

 

memory seems fine (has been tested and used elsewhere with no problems)

 

BIOS etc all seems OK - and no obvious option to change

 

anyone come across these things and can give me a clue of what could be wrong so I can maybe cobble together a coupld of working ones from the 4 on the floor in my shed/office??

 

 

tIA

 

Mike

[difinity]

If the memory has been tested with something like memtest, I'd look at the power supply, in particular swollen capacitors. What motherboard do these PCs have ?

[mikeprice]

capicitors all seem OK and memtest says memory is OK

 

no obvious problems with pOWer supply - althouGH I suppose that it could be wandering out of spec - how could I check that??

 

motherboard is Intel - label thingy saya E54511-203

[difinity]

Stick an oscilloscope on the outputs and look at the ripple. Failing that take the top off and have a look inside. Be mindful the capacitors inside could still have a charge in them, although you are only having a look, just don't go poking your fingers in.

I fixed a power supply a couple of weeks ago that had a couple of bulging capacitors in. The PC still worked but would lock up occasionally and act strange.