eBay Mobo - System power but no POST

FakeGamerGuy · April 20, 2018

I ordered a "new" motherboard, a Zotac GF9300-G-E, off eBay, along with an appropriate 65w CPU (Core2 Quad Q9505S). Being a good PC builder, I started by setting up the system on my desk, to make sure everything worked, before installing it in the case. I installed all the components, flipped the power switch on my PSU, and... the system is powering on by itself? GPU, HDD, PSU fan, everything is on, except that the CPU cooler only spun for a second, then stopped. No video out, and the board didn't come with a speaker for beep codes (I'll try to pick one up today).

First troubleshooting step, reseat everything, remove GPU (CPU and board both have their own graphics), try again. Same result.
Swap to another, known good CPU. Same result.
Swap to another, known good PSU. Same result.

Different, slower RAM.
Known good RAM in all 4 configurations (none, slot 1, slot 2, both slots).

I checked voltage as the CMOS battery and got 2.7v. Not too low, but when I reseated the battery it stopped auto-powering. The eBay listing said it was pulled from a working server, so maybe the self-powering was a BIOS settings? I'm still not able to get video, and the CPU cooler still stops spinning after one second. I also installed a new battery, and verified the voltage is >3v, but saw no change.

The CPU cooler is a PWM Zalman I got a long time ago because I wanted to do thermal and noise testing between it and a low profile Noctua, but I never got around to it. Wondering if there was a problem with the fan, I connected a 240mm AIO and powered on the system. The fans this time kept spinning, but otherwise there was no change. The AIO uses a 3-pin connection, where the Zalman has a 4-pin, so I'm wondering if it's still getting voltage, just no PWM signal. When I kill the power, the Zalman twitches, which seems to support this idea.

I've even installed all these components in my Dell, which uses the same socket and was able to POST successfully with the BIOS properly recognizing the RAM and CPU.

I've tried the DVI from the video card, DVI from the mainboard, and VGA from the mainboard. The only video port I haven't tried is the HDMI, since my monitors don't have that. I also tried reinstalling the Celeron the board shipped with, but there was no change there, either.

Out of desperation, last night I pulled the CPU out and powered on the system with an empty socket. To my surprise, the Zalman cooler spun as expected, and continued to spin at 100% until I powered the system off. This makes me think that maybe there's something wrong with the socket? A visual inspection doesn't show anything wrong, but I gave it a light cleaning with alcohol and a q-tip, but saw no change after both the new Q9505S (which my Dell POSTed with), as well as with my known-good Q6700.

I'm kind of out of ideas at the moment. I contacted the seller to get some additional information about the board, specifically when it was last used.

To reiterate, I verified that the CPUs, GPU, RAM, and PSUs all are functioning correctly on another system, so it's exceedingly unlikely to be a problem with one of those parts.

Edit: I should also mention that, when the GPU is installed, the LED on the GPU lights up, but the fan doesn't spin. IIRC, the fan should always be spinning if it's getting power from the PCI-e slot, so this gives me confidence that the system is not booting/powering correctly.

Edit 2: I forgot to mention, I also tried to get video out using a GT710 with no luck, but the fan on that GPU did spin, where my GTX295 did not.

FakeGamerGuy · April 21, 2018

Our story takes an exciting new turn. Went to Fry's to pickup a PC speaker to listen to beep codes, but they were out. Then asked about POST cards, but the only one they sell is PCI (this board only has PCI-e), and they couldn't find it anyway. So I go back home and try to read beep codes with my multimeter. Absolutely no result. I figured the multimeter I have wouldn't be quick enough to read the codes properly, but it should be seeing something. I start probing around the board to check voltages on the BIOS chip and see 0, 6.6, 0, 6.6, etc. as I'm going across the pins. 6.6 seems like an odd voltage, but... ya never know, some chips might need their own special voltage. So I decide to test the CMOS battery, since I remembered testing it the night before, getting something a bit above 3v. Sure enough, 6.6v. Seems bad.

Then I notice the board is smoking and I yank the shit out of the PSU's power cable.

I switch the PSU off, jump the PWR OK wire to ground, plug it back into wall power, and switch it on. Multimeter shows 3.37, 5.15, 12.17, and -12.xx volts on all the pins that were connected to the board. I've put in a return/refund request to either get another board, or just get my money back.