New Gigabyte motherboard PC won't post

[lmcancu]

Re: New Gigabyte motherboard PC won't post

Received the repaired motherboad 2 days ago. It posted fine out of the case and it seems to be fine. I installed the original memory, CPU, PSU, video card and no issues so far. Of course, this weekend I will install it in the CPU case and do some more rigorous testing. I'm happy so far as it seemed that nothing else got damaged after the MOSFET blew. I'm running the memory at the lowest settings (5-5-5-12), STANDARD, and only providing 1.8v to be on the safe side. All other BIOS settings are at defaults.

[lmcancu]

Re: New Gigabyte motherboard PC won't post

Once I installed it in the case, it posted in the BIOS screen and lasted about 10 minutes before the whole thing turned itself off. It won't turn back on now, no post, no lights at all. Checked the PSU and its fine. Looks like I will have to purchase a new MB. I don't think its anything in the case shorting it. I checked the clearance and its fine. It worked in that case for over a year. Its an ANTEC Sonata case. I'm suspecting its just a coincidence that it broke while it was in the case.

[seanc]

Re: New Gigabyte motherboard PC won't post

Well you might as well take it out of the case and try again.

[lmcancu]

Re: New Gigabyte motherboard PC won't post

I'm now suspecting the Seasonic PS or the PCI-Express card (ASUS Geforce 9600 GSO). I got a hold of an ASUS motherboard with embedded video, and everything worked fine until I installed the PCI-express card. After about 30 minutes, the screen went dark, but the computer stayed on. I shut the system down and replaced the Seasonic with a cheap PS I use to test things but without the PCI-express card. System is up and running perfectly now. I didn't want to risk things so I haven't re-installed the PCI-express card.

I measured the voltages of the Seasonic PSU after the fact but I’m not sure if that is enough to say whether the PSU is bad or not. I measured the voltages (with a digital multi-meter) both with a little load (2 DVD drives) and no load.

1) Without the paperclip, the PS-ON# voltage is at 2.59 V
2) No load: 12v: 12.15V, 3.3V: 3.38V, SB 5V: 5.02V, -12V: -11.31V, 5V: 5.1V
3) Load: 12v: 12.35-12.55v, 5V: 5.02V, 3.3v: 3.38V
a. Note: The 12v varies from 12.35V-12.55 when I open and close the trays of the DVD drives.

I also measured the voltage during load on one of my other rigs which uses a S12II 500W power supply. The voltage during load is closer to 12V at 12.12v, and this is with everything connected, AGP video card, hard disk, 2 DVD drives, 3 fans, etc. When I open and close the DVD drives the voltage varies only 0.01v from 12.12 V to 12.13V. Could this be a further indication that the unit is indeed faulty? i.e. could there be a high amount of ripple on the line that is damaging the motherboard and the components?

[seanc]

Re: New Gigabyte motherboard PC won't post

How old is the S12 PSU which you are having trouble with?
Have you tried loading it more?

[lmcancu]

Re: New Gigabyte motherboard PC won't post

Its an M12, and its a little over a year old. I could try adding the hard disk to it to give it more load. Any other suggestions to load it up more? Is there any way to test the Video card without installing it in the motherboard, i.e. checking for continuity, etc

[MixMasta]

Re: New Gigabyte motherboard PC won't post

Don't you have a spare power supply? All the symptoms you describe say power supply to me... including Gigabyte supposedly telling you so.

[lmcancu]

Re: New Gigabyte motherboard PC won't post

Yes, I'm using the spare power supply right now I have and everything works fine. I'm trying to determine whether it was the power supply, or the video card that did the damage, as both are under warranty. What is interesting is that one of the 3 PCI-E connector ground pins on the video card is floating when I check for continuity. The solder is also slightly discolored on the pin. So its either the Power supply took the card out or the video card took the motherboard out. You mention that the symptons say power supply. What symptons makes you think so?