My computer likes being fondled

[SupSuper]

COMPUTER TROUBLES HO!

Ok, so every once in a while my computer decides to not boot. Everything turns on and starts up and everything, but nothing will show up on the monitor. (no signal, not just a black screen) Sometimes a simple reset will fix it. Sometimes I have to open it up and just mess around with random stuff until it'll get over itself, and there seems to be no relation with what I do to get it working.

This has been going on for a long while and it's so incredibly random it's annoying. Anyone got any ideas?

- My tower has no PC speaker so I can't tell if it beeps or not when it "doesn't boot".
- I know it's not my graphics card, I've changed that a lot.
- I've also changed my monitor so not that.
- Probably not the power supply since everything still turns on and starts up.
- It might or might not be my RAM, but I've tried various swapping and testing and it eventually comes back.

[MtlAngelus]

Hmm... I remember once I had a computer that would alternate between working and not working. As in, turn it on, doesn't work, turn it off and on again, it works, turn it off and on again, it doesn't work, etc. And it was perfectly laid out that way, so it would only work every second attempt at turning it on. Never figured out why tho.

That said, you might still want to test using another power supply. Our computer downstairs once stopped working. It would apparently turn on, and the small led on the front would lighten up too, but the computer refused to work and there was no signal on the monitor either. Although in my case it never got it to work no matter how much I fiddled with it. Then I changed the PSU and it worked perfectly again.

[bonz]

Perhaps the power button or the reset button have a loose connection.

On a similar note:
I have a system here that I was supposed to install a fresh Windows.
I made backups of important data then formatted and installed. That took about 3 hours (with some brakes), in which time the computer was running fine.

Then I noticed that it had no ethernet adapter, so I couldn't plug it to my router and I decided to plug in a new NIC.

After that, it didn't want to boot any more. Only two beeps and a black screen (stand-by), with everything else seemingly running.

I then noticed that the CPU fan wasn't spinning anymore. The fan itself is working fine on another connector, but with no spinning fan the BIOS won't allow to boot, since it fears that the CPU might burn out. The CPU's heatsink was indeed quite hot.

Now I'm left with the dilemma that I can't boot to disable the fan check in BIOS, because it won't allow me.

[MrBunsy]

Sup: Have you tried updating the bios? Or is it easy to add a speaker to the motherboard so you can further debug it?

Bonz: It might be possible to find a way to fake the fan running, is it possible to look up how the bios usually senses the fan is on?

[SupSuper]

Hmm... I remember once I had a computer that would alternate between working and not working. As in, turn it on, doesn't work, turn it off and on again, it works, turn it off and on again, it doesn't work, etc. And it was perfectly laid out that way, so it would only work every second attempt at turning it on. Never figured out why tho.

That said, you might still want to test using another power supply. Our computer downstairs once stopped working. It would apparently turn on, and the small led on the front would lighten up too, but the computer refused to work and there was no signal on the monitor either. Although in my case it never got it to work no matter how much I fiddled with it. Then I changed the PSU and it worked perfectly again.I guess the power supply is the only thing I haven't outright replaced. Sadly we don't have any spares atm so I'd probably have to get a new one and hope it works.

Perhaps the power button or the reset button have a loose connection.Well the computer reacts fine to the buttons. You can hear it power on / off / reset accordingly. It just doesn't show anything on the monitor.

Sup: Have you tried updating the bios? Or is it easy to add a speaker to the motherboard so you can further debug it?Bios is updated, yes. I have no idea how I'd go about getting a speaker for the motherboard.

[MrBunsy]

Bios is updated, yes. I have no idea how I'd go about getting a speaker for the motherboard.

No old computers you can steal one from? There should just be a socket somewhere on the motherboard to plug one in.

[Vader]

COMPUTER TROUBLES HO!

It could be the AGP/PCIE port, rather than the graphics card(s).

Now I'm left with the dilemma that I can't boot to disable the fan check in BIOS, because it won't allow me.

As MrBunsy suggested, fake the fan's presence. Just stick an old fan on those pins so the current has somewhere to go. That will probably trick the BIOS into think a fan is present.

You might even be able to make a makeshift jumper of sorts, though I'd advise against it lest you short your whole mobo. :/

[bonz]

Bonz: It might be possible to find a way to fake the fan running, is it possible to look up how the bios usually senses the fan is on?

As MrBunsy suggested, fake the fan's presence. Just stick an old fan on those pins so the current has somewhere to go. That will probably trick the BIOS into think a fan is present.

You might even be able to make a makeshift jumper of sorts, though I'd advise against it lest you short your whole mobo. :/
I do have a fan plugged in there: it's the current CPU fan, which does work when plugged into another connector.

[Vader]

Check the pins' solder on the back of the board for cracks, maybe?

*shrug*

[bonz]

Check the pins' solder on the back of the board for cracks, maybe?
I'll look at that when I have to disassemble it.

I have read about error beep codes a bit and didn't find anything specific for Phoenix BIOS ones, but it seems that I get a standard IBM beep code (1x long, 1x short) which means that I have some kind of RAM error in one of the memory banks.
Might try removing/swapping/exchanging those RAM modules.

[SupSuper]

So it looks like it be gremlins.

Really. My computer did it again yesterday, only no sort of budging or messing around would bring it back. I was ready to consider it deceased.

My dad spent all of today pretty much swapping out and around everything, eventually rebuilding the whole thing from scratch. And it seems to work again. Even though the build is still exactly the same as it was before.

Choices are down to critical components like CPU and motherboard, in which case I'm probably screwed. In any case, I'm not turning off my computer any time soon.

[Vader]

If you're leaving your PC on forever then I suggest you get a decent RAM management/recovery tool. My old PC would get really sluggish when I left it on for days at a time until I started using some app I've forgotten the name of. That might be true for all PCs; I turn mine off over night these days so I wouldn't know.

I think the software was called MemoryMan or something. Can't really remember...

[SupSuper]

Well I can still restart, which clears the system up.

[SupSuper]

Well I've got a new power supply, new processor and just in case, removed a piece of RAM that seemed kinda troublesome. So far so good.