Problem with Dell 4100: Updated with the strangest problem ever.

[CU]

I am trying to fix a friends Dell 4100. She was talking online one day and all of the sudden the computer shuts off and the monitor goes blank. Now when you turn it on the monitor stays blank and the power light on the front of the computer doesn't come on. The power supply fans and all the other fans spin up. The HD also spins up. However I don't think it is loading the OS because the HD doesn't make enough HD accessing noise. The monitor and video card have checked out fine in other computers. And a working monitor and video card have been tried with the Dell with no luck. My guess now is the power supply or MB? Could a dead CPU cause this? One side note the Dell has 4 leds on the back of the case. None of them come on. According to Dell's website when these lights and the light on the front of the case are off it is the power supply. However a small led on the MB lights up and all the fans and HD spin up. Also this Dell has a none standard pin out for the main atx power connector, so I cannot test it. When I found the four diagnostic leds, I though wow that is great idea Dell then I looked at the main atx power connector's pin out and I lost all hope in them. To make things even better the connector for it will let you plug in a normal atx power supply. Anyway, any clues how to test for sure if power supply is the problem and where to get one cheap if it is? Also does anyone know if a standard atx MB will fit in this case?

 

[ElFenix]

dead board. if it was a cpu the thing would at least beep at you.

that atx lookalike plug pisses me off. and the fan header isn't standard either. its stupid. the other fan header on their 8200 board is standard, but not the first one.

 

[CU]

Well if I remove the sound card the the 4 leds gives me the code for bad memory. Also after removing all the cards and the battery and reinserting them the led on the front of the case comes on no matter if the sound card is in or not. But, the 4 leds are still all out with the sound card installed. Why do you thing it is the MB?

 

[Lonyo]

It can't be the PSU if the fans come on. On work experience at a computer tech place, a computer was brought in that wouldn't boot, we got a new PSU and it didn't help, so the technical guy figured it was the mobo, and I'd guess this is the case for you too.

 

[CU]

Well I found out somethings. It is not the MB or the power supply. It is the sound card. I get the same blank screen with it in another computer. I said in my last post that when I took it out I got a memory error. Well when I put some more memory in, it would run. Now for the strange thing. With the ram that was giving the memory error and some good ram it will boot and see both sticks. I take the good ram out and leave the orignal ram in it. Memory error again. I put that ram by itself in another computer. It runs fine. I put it back in the Dell it came from. It runs fine now. I have duplicate the many times now and always get the same results. Ram slots doesn't matter either. Some how the sound card is causing the the ram to not to boot even after the sound card has been taken out. My guess is an eprom or something is saving an invalid setting to the ram when it boots with the sound card in it, so after I take it out the ram will not work, and the other computers is reseting it. Also this only happens with that stick or ram not with the other two I have tried. Either way this is the strangest problem I have ever seen in all my years of working on computers. Has anybody else ever had a sound card to just die like this and cause so many problems? Now to find cheap new one.

 

[Dufman]

if it is a dell, it should be under warenty
if not, to to googlegear.com and get a sb dobly digital 5.1 for 38 bucks,