Desktop computer shuts down frequently without warning

[DerStrom8]

The hard part of this is yes the people here try to help. But some times it would be easier to be sitting in front of the computer when you are trying to help some body. The other thing is when you are limited on parts where you can't test them on a MB or in another computer too.

I hear you. Believe it or not I am actually fairly experienced with computer repair and other types of electronics. I've been repairing computers for several years, and somehow never came across an issue like this before. I tried everything I could think of at first, but when that didn't help I turned to you guys. Anyway, my point is that I've had to try to help people over the internet too, and it's very difficult. It is definitely easier to be there in person. That's exactly why I am thankful you stuck with me this long 

The amount of spare parts were definitely a limiting factor in this.

Anyway, thanks again.

Matt

[GMDemo]

I don't suppose your friend has a spare CPU that you could try.  You try to disable all the cores you are allowed to and see if that works.  If it does work the enable each core seperately until you find the bad core then just leave it disabled

[DerStrom8]

I don't suppose your friend has a spare CPU that you could try.  You try to disable all the cores you are allowed to and see if that works.  If it does work the enable each core seperately until you find the bad core then just leave it disabled

Hi GMDemo. Yup, that's exactly what I did with mine. I disabled all but two (The OS doesn't seem to want to even start up when running on only one core). I ran it on 2 for a while and then it crashed. It doesn't even begin to run on just the 1, so either core 0 or 1 are damaged, or there's a different problem. I ordered a new mobo for $100 (much cheaper than a new processor--no way I can afford that) and I'll have to see if that fixes it. I'm not sure if my friend has an extra processor or not. I would tend to doubt it, as he usually uses boards with different socket types.

I'll post back here when the new motherboard arrives and I can test it out.

Cheers,
Matt

[GMDemo]

I don't suppose you can just enable core 0 and 2 leaving 1 switched off.  I'm afraid the problem you are having sounds like a problem with the CPU, As it doesn't appear to be a heat problem perhaps reseating it would cure the problem

[DerStrom8]

I don't suppose you can just enable core 0 and 2 leaving 1 switched off.  I'm afraid the problem you are having sounds like a problem with the CPU, As it doesn't appear to be a heat problem perhaps reseating it would cure the problem

Nope, I can't. In the bios it gives me the option to run on 1, 2, 3, or 4 cores. It doesn't let me choose which ones. If I say 3, it'll use cores 0, 1, and 2. If I say 2, it'll run on cores 0 and 1, etc.

I reseated it but do not have any thermal paste to reattach the cooling fan assembly. I'm assuming that would need to be replaced every time I separate the fan and the CPU.

Matt

[dmdilks]

If you are really careful and don't touch any thing you can take them a part and put them back together.

All the  thermal paste does is fill the holes in the heat sink and CPU. To stop the air from getting caught in there.

Plus if you got it a part make sure you don't have any bent pins too.

[GMDemo]

Yes, don't run the computer without the thermal paste.  I have seen CPUs over heating when the paste hasn't been applied correctly let alone none whatsoever.  Hmm perhaps that would be interesting.....No don't try it.

BTW since I started this post someone else has posted and I do agree with what is said.  KEEP an eye on the temperature, if you can enable the warning in the BIOS for the CPU temp that would be good.

[DerStrom8]

If you are really careful and don't touch any thing you can take them a part and put them back together.

All the  thermal paste does is fill the holes in the heat sink and CPU. To stop the air from getting caught in there.

Plus if you got it a part make sure you don't have any bent pins too.

Good to know. I always learned to just get rid of all the old paste and apply all new any time you remove or replace the fan. If you're sure though, I'll think about it. By the way, I looked at it and it is not a pin-type processor. It's the pad type, so I don't think bending pins is an issue.

[DerStrom8]

Yes, don't run the computer without the thermal paste.  I have seen CPUs over heating when the paste hasn't been applied correctly let alone none whatsoever.  Hmm perhaps that would be interesting.....No don't try it.

BTW since I started this post someone else has posted and I do agree with what is said.  KEEP an eye on the temperature, if you can enable the warning in the BIOS for the CPU temp that would be good.

I'm not a newbie when it comes to repairing computers, trust me

I'm WAY ahead of you--I monitored the temperature in BIOS and set the alarm to go off at the lowest temp (40C). No alarms, so I don't think it's an overheating issue.

[dmdilks]

The pins are in the CPU socket on the board. Yes if you just take it a part and put it back together with out touching either the heat sink & CPU you should be fine.

[DerStrom8]

The pins are in the CPU socket on the board. Yes if you just take it a part and put it back together with out touching either the heat sink & CPU you should be fine.

It's the ball and pad type, no "pins" in the traditional sense, that can be bent. I did not touch anything with the thermal paste on it.

[dmdilks]

Yes they are not really pins in the since that you would call them that. But that is how we all call them that.

In all the CPU's that I even had I only had one that was bad.

[DerStrom8]

Hello again everyone.

Yesterday I had the chance to start disassembling parts of the board (removing heatsinks, etc) and found that the primary D-pak FETs were getting a lot warmer than usual. Some of the heatsink pads were not properly covering one or two of them, and it appears some of it was actually melted. I'm going to have to test some of the FETs, but I'm going to have to figure out the best way to test them in-circuit. Any thoughts or suggestions?

Thanks,
Matt

[DerStrom8]

Here's an image of the devices I'm concerned about:



The label appears to say K3918, but I cannot seem to find a datasheet for them. Might someone have an idea of what they are, and a good way to test them? I've already tested their resistance between each pin, and they seem to vary. I'm not exactly sure what resistances are normal and what are not though. Hoping someone can fill in a few blanks

Thank you!
Regards,
Matt

EDIT: My apologies, I did not realize the photograph was so big.

[DerStrom8]

Well guys, my new motherboard arrived the other day, I installed it yesterday and the computer was running fine. Until today. It just shut off randomly again. So apparently it wasn't the motherboard after all.

Any thoughts? The last remaining possibilities I can think of are possible issues with the video cards (intermittent shorts, perhaps) but it would have to be on both of them. I've tried all combinations of the video cards, both single and both inserted, and still had the same problem. Going to have to find someone who can lend me a video card to test it. If it's not the video cards, the only remaining possibility is the processor, which is another $140 down the drain....