PC occasionally won't boot.

[Fuzziekiwi]

This problem has been going on for over a year now but it happens only once or twice every one to two weeks that I have ignored it for this long. I RMA'd the motherboard because I thought it was a motherboard issue but it still persists. There are no bent pins on the CPU, and the CPU isn't damaged. A few times turning it on and off and it will boot just fine. Motherboard manual does not list anything troubleshooting related- nothing about the beep codes or led blinking light.

I have previously tried:
- Resetting the CMOS
- Checking if all the plugs are plugged in

So, the symptoms:
Turn on PC
- Monitor doesn't turn on
- CPU fan turns on
- Back case fan doesn't turn on, as well as the front panel fan
- Motherboard speaker buzzes once (I think)
- Sometimes turning it off will result in motherboard flashing blue led

SPECS:
i7-4790k
GTX650 TI BOOST
G.Skill 8gb 1866mhz ddr3
MSI Z97S SLI Krait Edition

Any other questions, ask. Thanks!

 

[burtman88]

Maybe it's your power supply, just not providing corrected voltage at that moment. I have had a issue for 3 years where my usb ports don't work where i have to manually turn power supple off from the back. Different mobo ad stuff, different psu since then. Mine problem i believe is my case, to be honest doesn't really bother me.

 

[clarkjd]

What HDDs (or SSDs)are you using?
If your HDDs are still trying to spin up to speed, that could cause the issue.

 

[Chicano]

Well, with the motherboard discarded as a possible cause, and having checked all power plugs, I would blame the PSU. It may be so weak it doesn't power up everything (like front and back case fans). A single BIOS beep indicated all normal so the computer may be starting up normally but not the rest of component as the GPU and fans.

Suggestion 1 - A way to insure the computer boots the first time, is pausing the BIOS post with key Pause/Break.. wait say 10 seconds and press the same key to continue. If it doesn't have effect, increate to 15 seconds and so on till it has an effect. Combine this test with disconnecting the rear and front case fans. This would allow time for the PSU to preload the mobo capacitors and components for normal boot.

Suggestion 2 - would be disconnecting front and rear case fans and run the computer like this for a week or two... long enouth for the issue to occur. After that you should have your proof of weak PSU... or you could ignore this suggestion and try a different PSU if one is available, or buy a new one.

 

[Fuzziekiwi]

What HDDs (or SSDs)are you using?
If your HDDs are still trying to spin up to speed, that could cause the issue.

SSD 24gig samsung 840 evo
1TB 7200rpm WD
500gb 7200rpm WD
500gb 7200rpm WD

 

[Fuzziekiwi]

Well, with the motherboard discarded as a possible cause, and having checked all power plugs, I would blame the PSU. It may be so weak it doesn't power up everything (like front and back case fans). A single BIOS beep indicated all normal so the computer may be starting up normally but not the rest of component as the GPU and fans.

Suggestion 1 - A way to insure the computer boots the first time, is pausing the BIOS post with key Pause/Break.. wait say 10 seconds and press the same key to continue. If it doesn't have effect, increate to 15 seconds and so on till it has an effect. Combine this test with disconnecting the rear and front case fans. This would allow time for the PSU to preload the mobo capacitors and components for normal boot.

Suggestion 2 - would be disconnecting front and rear case fans and run the computer like this for a week or two... long enouth for the issue to occur. After that you should have your proof of weak PSU... or you could ignore this suggestion and try a different PSU if one is available, or buy a new one.

CX600M. I don't have the money to replace this so I will go on with your suggestion once the problem occurs again.