Computer randomly shuts down on its own

[TechFreak99]

Recently my computer has started shutting down on its own. Not in a safe controlled shut down, no this is a complete drop. After which the power light on the front of my case blinks on for 3 seconds and off for 3 seconds. When pressing the power button the computer does not power on. I am only able to get the computer back on by either flipping the switch on the back of the P/S or unplugging the power cord for several seconds.

It started doing this when I powered down the system for one day while I would not be using it. When I powered it back up the next day several hours later it shut down on its own. It is completely random that this symptom occurs. However I have found it not to have done this during an entire week of being on standby.

Is this a motherboard or P/S issue?

I have performed a test on the P/S using a volt meter through jumping the leads to get the P/S on.

These are the results I got:

Normal values/ Actual Values (No load)
Pin#

1 +3.3V 13 +3.3V 1 +3.27V 13 +3.27V

2 +3.3V 14 -12V 2 +3.27V 14 -11.45V

3 GND 15 GND 3 GND 15 GND

4 +5V 16 PS-ON# 4 +5.13V 16 PSON

5 GND 17 GND 5 GND 17 GND

6 +5V 18 GND 6 +5.13V 18 GND

7 GND 19 GND 7 GND 19 GND

8 PW ROK 20 RES 8 +5.10V 20 RES

9 5VSB 21 +5V 9 +5.10V 21 +5.13V

10 +12V 22 +5V 10 +11.94V 22 +5.13V

11 +12V 23 +5V 11 +11.94V 23 +5.13V

12 +NC 24 GND 12 NC+3.27 24 GND


Power supply is a Sesonic Model# SS-380-HB Active PFC-F3
Motherboard is a MSI K8N-Neo4 Platinum MS-7125
Processor AMD 64 939 3200+
Memory Kingston 1.5GB
Windows XP Pro

If I left out any key information please let me know.

 

[DrMrLordX]

It sounds an awful lot like a PSU problem. If I were you I'd look at the PSU's fan to see if it's spinning up or otherwise check to see if the PSU is overheating. Do you have any issues with case air flow?

 

[Lunyone]

Sure sounds like a possible PSU issue. Do you have a dedicated GPU hooked up too?? I'd also double check the temperatures out the back of the PSU when you start to load it up. If it gets pretty hot (don't touch any metal parts, just hold hand away from output fan) than you might possibly have a PSU issue. It's also possible that there might be other parts getting hot over a period of time too, so let's not rule out other options at this point.

Do you have another PSU that you can use to see if that fixes your problems? Maybe from a buddy's rig??