I blew up 2 PSU's. Need help late 80's, early 90s style!

Hey guys.

Where i work we once every few years build up OLD pc's for dos programming for the machines we build.

I was given the task to build up an old rig, and the weapon of choice became:
Penitum 120mhz
8mb RAM
1080Mb HDD.

I hooked it up, and it was working. So i opened it and removed a bunch of not needed hardware, and then i had to run a few tests on som gfx cards we had. Threw all this, the machine worked, no issues.

Then i took the CPU fan, took off the sticker and gav it grease, because it was noisy. Stuck it all back together and stuck in out own ISA card thats used for controling the machines.

Hooked up the puppy and... nothing... no signs of life what so ever. That was until it said pufff and the psu blew up. I opened up and this PSU has 2 chips mounted on the Aluminium coolers, both blown the top off.

On the tops it says "JAPAN NT 407 FF 59"

We had another machine that was identical almost, tookt he PSU from it, hooked up and, and did a repeat. Blew up the PSU.

Same chips, only this time it was only one chip, out of 2.

I only have 1 PSU left, this must NOT happen again. Would anyone (and im looking for older generations here) happen to have any idea what could cause these chip to blow up and not the fuse?

Pictures:




Big versions of pics:
http://peecee.dk/uploads/042011/DSC02342.JPG
http://peecee.dk/uploads/042011/DSC02341.JPG
http://peecee.dk/uploads/042011/DSC02340.JPG

Thank you.

220v instead of 110v selected, grounding within the PS, or faulty unit would be my first guesses.

Edit: You could have dropped some grease/oil on the MB when you oiled the CPU fan.....MB short + old PS = blown up parts.

corruption said:

220v instead of 110v selected, grounding within the PS, or faulty unit would be my first guesses.

Edit: You could have dropped some grease/oil on the MB when you oiled the CPU fan.....MB short + old PS = blown up parts.

Click to expand...

Im in Europe, i hope that explains the 220v setting.

no grease anywhere in pc.