Computer randomly turns off and can't be turned on for awhile after.

[Hachuu]

My friend's computer started to randomly turn off, and then we'd have to wait like 10 minutes before being able to switch it on again. When it turns off, the power led is still on which is pretty strange. So we got new parts: power supply, mobo, proc. All quality pieces so that isn't the problem, and it still turns off randomly. Any ideas? Thanks in advance.

 

[johnjkr1]

Try running it straight into the wall, if you do not have it set up that way already. In addition, what kind of temps is it running at? Is the heatsink installed proplery?

 

[Hachuu]

It's running straight from the wall, and cpu temps hasn't broken 32 before shutting off. We just ran it with minimal hardware also. Only cpu and vidcard, and let bios run for awhile. Once we tried quitting out of bios it shut off.

 

[johnjkr1]

So then I would focus on the parts that made the move from the old broken pc, especially the vid card. Why not let him borrow yours and see what happens?

 

[Hachuu]

yea we tried a different vid card, same thing. Tried different ram, have yet to try diff hd, but we've unplugged the hd and it still shuts down. Can it be a case problem? Never heard of it but...stretching for ideas now. Thanks for your help by the way.

 

[johnjkr1]

It could be a grounding issue, those are rare. Did you use the screws to mount the motherboard? Can you expalin, "once we quit out of the bios it shuts down"? also, check and make sure the screws go to a metal hold and are not touching the bottom of the bare motherboard. Switched motherboards do not always line up the same.

 

[Hachuu]

Yea I was thinking a ground issue, how would I go about checking this? Oh yea, the case is pretty cheap and it uses these weird clips to mount the mobo on. You push two sides together to put the clip into the case. (Not sure if you can picture that or know what I'm talking about)

For the bios, we were running it fine in bios for like 10-15, but once we tried to exit to restart, that's when it shut down. Seems like whenever is needs to use more power or something.

 

[johnjkr1]

you can just build the PC on some cardboard or some non-conductive material. I do it on a shoebox.

When you say "shut down" when leaving bios, do you mean SHUT OFF, or it just fails to display anything?

 

[Hachuu]

the computer turns off. although the power led will still stay on.

 

[johnjkr1]

hmmm, that sounds interesting. If the lights stay on and the fans keep spinning after you exit the bios, it is just failing to post. What do you do to get it to come back up? Unplug it?

 

[Hachuu]

The fan is not running, everything shuts off, except for the led. We just have to wait a few minutes before pushing the power button even works. For the past few tries, it hasn't even been booting up. We are trying to take everything out of the case right now, to build on cardboard.

Hmm...same problem out of the case, now it doesn't even turn on, the fan attempts to start, and turns like a 1/4 of a turn and that's it.

 

[johnjkr1]

reset the cmos and give it another try. also, what kind of cpu/memory is in this computer?

 

[Hachuu]

amd 2500+ barton
crucial pc2100
asus a7n8x mobo
antec true 380
ati 9800xt

 

[johnjkr1]

what speed are you running the memory at, and what speed is the cpu detected at? also, are you using the amd heatsink? I have seen the exact same problem when I used a speed controlling fan plugged into the motherboard, wierd, but it happens.

 

[Hachuu]

memory at 133 I think, whatever default is, I upped the fsb to 166, so cpu is running correctly at the 2500+ speed. using a vantec aeroflow hs/fan.

 

[mechBgon]

Yeah, if you have the Antec True380's fan-monitoring wire plugged into a fan header on the motherboard... don't do that. Also, your system really calls for at least PC2700 memory so it can be run synchronously to the CPU's bus. Confirm that the Radeon 9800XT does have its auxiliary power pigtail plugged into the power supply, and double-check that your heatsink is installed this way.

Is it using the stock heatsink or aftermarket, by the way? What kind of thermal-interface material (grease/patch)?

If it works outside the case on cardboard, then the symptoms may be indicating that it was grounding out somewhere, like johnjkr1 said. One of the possibilities is that your case's front-USB wiring was plugged in incorrectly, or that the EMI springs on the I/O shield were getting into the USB or network jacks on the rear and grounding out in there. Any of that sound like a possibility?

The board has speech diagnostics, but I don't know if they'll be useful or not. Plug headphones or powered speakers into the green audio-out jack on the rear of the board and see what it has to say.

 

[mechBgon]

Originally posted by: Hachuu
memory at 133 I think, whatever default is, I upped the fsb to 166, so cpu is running correctly at the 2500+ speed. using a vantec aeroflow hs/fan.

That's overclocking the memory from PC2100 to PC2700 speeds. Do you have some PC2700 you could use in place of the PC2100?

 

[Hachuu]

having 2100 ram should still run fine with this setup, 2700 would just be for perfomance, which we're not worried about atm. HS is installed correctly . We used the thermal material that came with the vantec aeroflow which has worked fine for some other computers I have built. We just moved the computer to a different room to try a different power outlet and it turned on, so maybe that was the problem. I'll update that in a bit.

Thanks alot for both your help.

Update: Eh, same problems......

 

[johnjkr1]

I'm going to blame the pc2100. Try setting the cpu fsb to 133 and leaving it there, see what happens.

 

[Hachuu]

well the problem is that the computer sometimes won't even start up. It seems like it's not getting enough power or something. We reset the cmos anyways, so everything should be at default right now, which is probably 100fsb.