PSU or MB? Faulty Line?

[JoshM20]

Hey Guys,
My Girlfriend brought her old Tower to me to work on it. I have worked on a few Pc's and have troubleshooted a few. I'm not a tech but I'm not new to them.

Anyway here is my problem, when she brought it over it would not turn on. Nothing at all, no power, no post, no anything. So I got my DMM and started to check the voltages. There was voltages on the 24 pin connector, so i thought it may be the switch.

I checked the switch and it seemed to be ok, so I unconnected the HD and used a jumper to check the PSU. Everything spun up so I was confused. I decided to use a jumper on the MB and it worked.

Everything spun up and I was able to get into XP and repair the rest of the pc, mainly virus and malware. So I decided to try to put it into hibernation with switch and it worked. I could even cut it off with the switch, although the fans did not shut off.

After I had removed the virus/malware/spyware I defraged and ran clean disk. So I thought it was time to take out the jumper and see if it would cold boot. Sadly No same symtems as before, I was going to use the jumper and take it out while in the system to see if it would run or shut off, but I decided I should ask before I tryed that.

Any idea of what this could be? Seems to me like a line on the MB may have burnt up. Not sure though, any suggestions would be great.

Thankx
Josh

 

[Mondoman]

What jumper are you referring to? What are the model numbers of the MB, PS, CPU, etc?

 

[JoshM20]

Its a Gateway 5200XL
It has a Intel® Pentium® 4 530 Processor 3.0 GHz
Intel 915G chipset
305 watt PSU +3/17a +5/22a +12/18va +12/vb
Intel (Augsburg) 915G Motherboard

And the jumper I was refering to was jumping the Ground to pin 16 or PS-On/green wire. I jumped it with a paperclip

 

[Mondoman]

Why do you think the power switch and/or the wires to it are OK? How did you test them? It sure sounds like a power switch problem if I understand correctly.

 

[JoshM20]

To be honest the power switch is what I thought and suspected was wrong. The only reason I say that it may have been something else was because when the pc was on I was able to put the pc into hibernation and turn it off. If the switch was at fault and there was a break of voltage in the line it should not have done this. Atleast that is what I thought. I may be wrong though.

 

[JoshM20]

To add to it, I talked to her about when it first happend. She said it happend after a power outage and when she turned it back on it ran for a while then while in windows it made a "woosh" and turned off. Sounded like she was saying the voltage dropped off gradually. Maybe this can help if anyone has had experience with this before.

 

[Mondoman]

If not the power switch, the power supply would be my next bet. They often fail partially.

 

[JoshM20]

How would I rule out the MB? Still something seems odd to me.

 

[JoshM20]

I should be able to change the switch with any other switch I have around right?

 

[Mondoman]

Just unplug the switch's connection from the MB and manually bridge those two pins on the MB with something conductive like a screwdriver blade (momentarily, of course!). If the system turns on and off fine with that, then the switch or the wiring to it was the problem.