I've been building and troubleshooting PCs since the early 90s, but I'm having an issue with my father's PC that I'm having a heck of a time isolating. I put the machine together for him back in November, and he's had no issues until this week.
After the machine sits overnight, it won't boot. It won't even POST. The LEDs on the motherboard come on, so power is getting to the board and when I hit the power button, the CPU fan spins once or twice and then stops. I've tried removing and/or reseating every blasted chip / card / connector on the board, checking for shorts, etc, and it makes no difference. I finally found that if I short the "clear CMOS" pins four or five times in a row, it eventually springs back to life and boots.
At that point, I can shut down the machine and it will warm or cold boot fine. My thoughts are obviously that it is a problem with the motherboard or PSU. I've checked all the caps and they all seem fine. I've replaced the battery. I've re-flashed several different BIOSes without problem (speculating that BIOS was corrupted). I've even tried unplugging it and letting it sit a couple of hours (also with the battery pulled) and it starts up fine when I plug it back in and hit power.
However, *every day this week* when my father tries to start up the machine 12+ hours later, it again refuses to POST, and I go over and reset the CMOS, go through all the motions, etc. I'm pulling my hair out.
If anyone has any ideas, I would be most appreciative! My next step will be to buy a replacement motherboard, which is a significant outlay of expense.
System
Motherboard: GA-Z68X-UD3H-B3 Rev. 1 Socket 1155 (Tried both the U1L UEFI bios, as well as reverting to the Award F11/F12 bios)
CPU: Intel i5-2500K (stock speed)
Video: Intel HD3000 (Integrated video on 2500K cpu)
Ram: 8Gb Corsair DDR3 (4Gbx2) (Passed mem tests just fine)
After the machine sits overnight, it won't boot. It won't even POST. The LEDs on the motherboard come on, so power is getting to the board and when I hit the power button, the CPU fan spins once or twice and then stops. I've tried removing and/or reseating every blasted chip / card / connector on the board, checking for shorts, etc, and it makes no difference. I finally found that if I short the "clear CMOS" pins four or five times in a row, it eventually springs back to life and boots.
At that point, I can shut down the machine and it will warm or cold boot fine. My thoughts are obviously that it is a problem with the motherboard or PSU. I've checked all the caps and they all seem fine. I've replaced the battery. I've re-flashed several different BIOSes without problem (speculating that BIOS was corrupted). I've even tried unplugging it and letting it sit a couple of hours (also with the battery pulled) and it starts up fine when I plug it back in and hit power.
However, *every day this week* when my father tries to start up the machine 12+ hours later, it again refuses to POST, and I go over and reset the CMOS, go through all the motions, etc. I'm pulling my hair out.
If anyone has any ideas, I would be most appreciative! My next step will be to buy a replacement motherboard, which is a significant outlay of expense.
System
Motherboard: GA-Z68X-UD3H-B3 Rev. 1 Socket 1155 (Tried both the U1L UEFI bios, as well as reverting to the Award F11/F12 bios)
CPU: Intel i5-2500K (stock speed)
Video: Intel HD3000 (Integrated video on 2500K cpu)
Ram: 8Gb Corsair DDR3 (4Gbx2) (Passed mem tests just fine)