psuill

P

peahouse05

Dedicated Cruncher
Joined
Jan 3, 2006
Messages
734
Reaction score
0
Hello,
Moved pc between rooms, tried to start, PSU led lit briefly then nothing. During removal of PSU from case noticed a yellow wire (+12V dc) loose from from a floppy power plug. Must have flapped around and touched the case. Removed PSU cover, 240V primary fuse ok. Secondary of transformer should be ok or there would have been a bang and smoke. But what about the bridge rectifier? Have not done any detailed tests yet but surely there must be some protection against short circuit on the low voltage side. Does anyone know?
Regards
peahouse05:confused:
 
oops, bugger ...

... surely there must be some protection against short circuit on the low voltage side
Click to expand...
What! ... and loose a new sale.

The Floppybootstomp may have "played" with the innards of a PSU ... it is annoying the amout of systems you see that have been shutdown, never to start again. :(
 
muckshifter said:
What! ... and loose a new sale.

The Floppybootstomp may have "played" with the innards of a PSU ... it is annoying the amout of systems you see that have been shutdown, never to start again. :(
Click to expand...

If it is ....ed thought of using the PSU from my other old PC but unfortunately the P8 and P9 connecters to the MBs are different. Time to call in a favour from my old employer and borrow an oscilloscope to investigate the low-voltage side. At least I do know something about this stuff.
Still cheerful,
peahouse05
icon6.gif
 
Hi,
PSU on bench, checked device plugs with multimeter. Blue wire on P8 mb plug only -7.3V (should be -12V). Multimeter probes don't fit inside mb plugs but small lengths of 1.5mm mains cable earth conductor does. All ok but fan didn't run. Took off cover removed fan checked fan supply, only 7V. Cleaned and replaced fan, still no good. Remembered having to draw current to check laboratory psus years ago. Used old hdd to draw current, fan ran and blue wire jumped to -10.6V. Refitted to pc, one beep, so psu must be ok.
Still a mystery really but something in the above did the trick.
Regards,
peahouse05:)
 
Jolly good ... for future reference ... put a wire from Green to the Black and the PSU will start-up. ;)

:thumb:
 
Back
Top