Computer just powered down... help?

mriviecc

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Jul 26, 2009
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My computer was running fine.... and suddenly it just shut off. As soon as it shut off it looked like it was trying to power back on but only very briefly, and now its just dead... hitting the power button at most starts to spin a system fan for a brief second then nothing? I don't know what happened. I'm thinking it the power supply went, but I'm not sure. Anybody have any ideas about what it might be and if it is the power supply.. how i can test it? Thanks and really appreciate any help.

 
Solution
More than likely, it is the PSU.

Try to borrow a known good PSU. Or better yet, see if you can test your PSU in another working system. If you cannot do that, try to borrow a DMM to measure the voltages. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can...
More than likely, it is the PSU.

Try to borrow a known good PSU. Or better yet, see if you can test your PSU in another working system. If you cannot do that, try to borrow a DMM to measure the voltages. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead.

Our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems
 
Solution

mriviecc

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Jul 26, 2009
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I did what you suggested and disconnected the main lead to the motherboard and disconnected the the other 12V lead from the motherboard powering hte CPU and used a paper clip to short the green wire to the black wire. I just touched on end to the green and the other to a black right next to it. The same thing happens..system fans start to spin for a brief second.. not even a full second and.. and it just dies while i still have the two leads connected via that paper clip. I don't know much about batteries.. but would you say that is a failed test and the PSU is dead?

This might sound crazy but i really hope it is the psu and not something else.. more severe.. like a mobo or cpu problem. Thanks for any help and appreciate it.
 

mriviecc

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Jul 26, 2009
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Thank for the response. Really appreciate it. This psu is a little over a month old so i'm going to try and rma it back to newegg for a replacement for the time being and probably buy a better quality one as well. The psu that died is an:

OCZ MODxStream Pro 700W

I heard good things about it. Maybe the one i received was just one of the bad ones of the batch.
 

mriviecc

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Jul 26, 2009
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I RMA'd the dead psu. I called OCZ and told them that it fails the paper clip test, and the tech rep. said that if it fails that then it's a dead psu. I got an rma from newegg so its headed back there. I did get my hands on another psu, but it is only a 400watt psu.

I'm a little leary to connect this up to my system. Is it okay to just connect up the main 20pin connector and the 6pin 12v connector for cpu, sata connector to the cd and hd and remove the vid card then power on without risking damage to my system?