computer wont turn on

[lumis]

i had a friend of mine bring his computer by for me to take a look at.. all i got from him was "it wont turn on"..

so i hooked it up, sure enough, it wouldnt turn on.. so i pooped it open, there is a green led on the mobo that comes on when you attach the power cord to the PSU.. so i'm guessing its getting power.. just to be sure i hooked up another PSU that i know works, same thing, green led, but it wont turn on.. now normally i would hook up a switch from an old computer i have sitting around, but this is a pre-built computer, so things get a little hairy from here.. it doesnt use standard "jumper pins" to attach the switch, hdd led, power led, etc..

it has its own little cable that hooks up to the mobo, runs to a little circuit board, than then runs a little ribbon cable to the switch.. i'm guessing either the switch, or one of the two cables has gone awry.. there doesnt appear to be any way to get to the power switch to have a good look at it, the front case/bezel/thing does not come off.. so i cant run any tests on the switch itself.

so i'm at a bit of a loss here as to how to procede.. its not like i could take the motherboard out and put it inside of another computer..

its a dell dimension 4500..

anyone have any ideas?

[Marty2003]

If you look closely at the motherboard at the "jumper pins" where the power switch is connected the two individual pins for the switch might be marked by PWR_SW or something similar. You just need to short circuit those two pins for less than a second to check if the comp will start.

[lumis]

marty,

my apologies.. that was supposed to be it !doesnt! use standard jumper pins

[hellbringer]

well a few pics might help if u can get them, otherwise there has to be some way to get the the power switch u need to follow them cords and find a way to access everything.

they put it together somehow

[smearbrick1]

Has your friend been fiddling with his computer internals recently? Is the processor seated correctly? Every power on issue I've ever had was related to the processor and how it was seated. Especially the older PII/PIII cartridge type processors.

[Skith]

If changes have been made to the BIOS, or if hardware changes have occured, you might consider clearing the CMOS. There should be a jumper to "Clear CMOS" and if there is not, you could try removing the small battery on the motherboard for several minutes, then put it back in. This should restore the bios to default settings (you will have to redo any changes).

This happend a few times with my Abit board (although it is an AMD system). Also check to make sure the power connections are tight, and that the fans are operating. Make sure that the RAM sticks are firmly in place.

[dawnmk]

Same problem here with a dell. The case does open...although not easily.(have to take of the top and bottom and then the front will come off) Had the switch out and the people at the dell dealer here looked at me like i was crazy. They apparently think it is the power supply that is fried.

[Skith]

I have heard of problems with Dell PSUs failing and being underpowered. I have no experience with them myself.

A bad or failing PSU can cause all sorts of odd behavior, and is one of the most overlooked cause of problems. Unfortunately Dell uses a proprietary PSU mounting/design so you would have to get a replacement from Dell, if it is the cause of your problems.