No POST (sometimes) - need more ideas

Karissa

Junior Member
Aug 24, 2005
4
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Hi, it's my first pc build and it's not looking good.
If the machine is cold when I power it on, it will POST ok. However, after running it for a little while and powering it down, I cannot turn it back on again. There would be no post (monitor on standby), no light flashing at the keyboard, it just keeps running and fan spinning. If I turn it off again, unplug power and plug it back in, the fan would kick up spinning loud, still no post and no lights to the keyboard.

I have tried with minimum config (mobo + cpu + 1 stick of ram + video) but it's the same result. Sometimes it will POST, sometimes it doesn't. The only way it guarantees to work so far is if I let it sit idle with power off for 30min and try again, then it normally POST fine. Once it post, it can run fine for several hours (i haven't tried longer time).

I've tried resetting CMOS, changing bios chip, RMA'ed mobo, using 1 stick of RAM only on different slots. Video and HD work when tried on another computer. So the only parts I can think of are cpu and power supply. Am I missing something? It's my first build too so I hope I haven't connect anything wrong to cause this. I think it's the psu since it does POST some of the times. Let me know what you think!! Any comment is appreciated.

How do I check the psu health? I read here that I can just check the voltage. It looks to be on track. Is there anything in particular I can check? I'm new in this so please provide details. Thanks.
 

Nocturnal

Lifer
Jan 8, 2002
18,927
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Sounds like it is overheating. What type of thermal compound are you using? Have you tried reapplying the thermal compound as well as reseating the CPU? Especially when you mention that you leave it off for a while and then it will work again. Heating is the first thing that comes to mind.
 

Karissa

Junior Member
Aug 24, 2005
4
0
0
It only has a problem if I turn it off completely and on again, restarting is fine. So just before powering it down, I would restart into bios to check the temperature. The temp never goes higher than 45oC so I don't think that's overheating yet. The system is also stable once it boots fine (never hang or bsod).

I have reseated the cpu once. It's a shuttle system so I used the thermal paste supplied with the barebone. I can try arctic silver but do you think the temperature it reads are critical?
 

Karissa

Junior Member
Aug 24, 2005
4
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I was hoping to try that last. So please let me know if you have any other suggestions!
I can get a hold of a 200W psu easily but that's not enough power. I can likely try a 350W one but it'll be a pain getting it.

Any other ideas?