PC turn off itself 3

[baha]

Hi,
I just finished building my PC and i got a problrm with it. It is Amd 1800, MSI KT3 MOBO, nvidia 440 Video, 500w Power. What happens is i turn on pc and sometimes it works for ten minutes, sometimes it does not start. I think it may be a power supply, because after it turns off i can not turn it back for some time, i have to wait. Sometimes it turns off because i open CD-rom or plug speakers or insert Floppy or just touch it. I checked all connections they are good. I have cheap Power supply, so i think it overheats, but my PC Temp monitor says the CPU is around 40-45 C, and system is around 35-40 too.
The only thing i do not understand why it turns off when i touch it or just open the cd-rom.

Thanks in advance for any input.

P.S: Tonight i will try to plug another Power supply, we will see.

 

[Dreadson]

I would also say the powersupply. My computer poweroff switch is also ultra sensitive, and it turns off when I bump the computer. If the new powersupply doesn't work (even if it is the right voltage), try checking the shutdown temperature in your BIOS. On mine, somehow, it got set very low and kept turning off my computer.

 

[baha]

Actually i set the CPU shut down temp to 90 C.

Is it possible that Win XP pro causing problem, because I installed it and it took more than 25 minutes, and PC did not shut down or whatever. After that i start getting this problem, maybe i was just lucky to install Win XP before Power supply overheated.

Another thing is my PC does not start when the case is open, I have to close it, and I do not think the case has some censors, as it is cheap one.

Thanks

 

[jhall01]

Okay let me get this straight...The computer won't start if the case is open...I guess there is a first for everything.

The only thing I can think of is a grounding problem possibly, or dirty power. Dirty power is easy to fix with a voltage regulator.

as for grounding check to make sure your mother board is grounded properly and the powersupply is grounded properly. If you just barely tap it then you have a weak connection somewhere. proper mounting your MOBO is the most important thing for protecting your PC.

If you still think it is the Power supply try buying a lower wattage for cheap like a 250w or a 300w and test it.

if it works then you know your powersupply is bad.

Also make sure all your fans are running. If you are real savvy you can try to up the voltage on the powersupply fan to make it run faster but this can be dangerous. If you still think it is a heating problem this alway helps.

Open the CASE take a big box fan and set it next to the PC. put it on hi and let it blast the PC full of air while it is on. If it still shuts off i think it is not a heating issue

 

[baha]

How to ground MOBO and Power supply? I have my other PC which works and has 300W PS, so i will try to use it tonight.
I will check mounting again too.

 

[crazy888s]

It really sounds like something is shorting out somewhere.

When you mounted the motherboard in the case, you did mount the board on top of metal supports didnt you? I mean, you didnt screw the motherboard right into the case...? And make sure that none of the screw heads are touching any part of your motherboard aside from the silver-screw hole areas.

 

[jhall01]

yeah check your mounts and switch the powersupply and let me know how it turns out.

 

[Eskimo69]

It sounds like when you touch it you are becomming ground are you one of those who bust the ground pin off your power cable to get it to fit in a old wall outlet that means most likely your case is holding a charge which could be very dangerous on components but I think if it was doing that you would get zapped. I would go out and buy a new 300 watt power supply. And make sure your mobo is tightly connected to your chassis. and the thing about your case being open. alot of cases have just a little switch that connects to your motherboard from your chassis on the chassis security header.

 

[baha]

Thanks for help guys.
I fixed it.

First i connected my other Power Supply, it did not start. So i start checking the MOBO, and i remembered that when i was installing it i screwed one of the screws which hold MOBO to chassis in a wrong spot, and i did not do anything with it as i had already screwed in 5 screws, so i thought the 6th screw will not be needed. This mounting screw was touching the circuit behind the MOBO, so to check if it was the problem i put isolator between screw and MOBO, and it worked with open case, with all the shaking i did. and still working.

Thanks very much for the help.