What is the position of the fuse in a pc power pack

[kingman26271]

Hello,
my computer system stoped powering up and i remove the power pack to check if it is working fine but it was not powering so i tried to see if i can fix it but i could'nt find the postion of the fuse to know if the fuse is ok or not.
please if you can help me in getting through to the fuse i will appreciate it, it is a dell pc.

 

[jsc]

I would say that if you cannot locate the fuse by sight, you shouldn't be poking around inside a PSU.

OTOH, you have nothing to lose. The PSU does not work anyway.

Before you start, do the paperclip trick:
You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=youtube_gdata

Use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

If you have any of the voltages, the fuse is not your problem.

Assuming the warranty has expired (otherwise you will void any warranty), open up the PSU. Look for the fuse somewhere close to where the power comes in. You should see it soldered to the PCB. The the resistance function of the DMM to see if the fuse is blown. If not, there is nothing you can do except replace the PSU.

Now you need to remove the PCB from the lower half of the case so you have access to the back of the PCB. Unsolder the blown fuse and replace it with the same size.

 

[megamanx00]

^+1

Make sure the PSU is properly discharged before poking around in it. We're not responsible if you fry your little brains out.