Question Video Card or PCIe slot problem


Jun 1, 2014
I put together a budget system with an old motherboard for my son to use for gaming and schoolwork in college. We had it running fine down here for a year with no problems. Then last month I shipped it up to him in the original box that the tower (case) came in with the styrofoam pads and all. When he got it, it wouldn't POST. No video or BIOS. I don't remember if he said that he was getting diagnostics beeps at that time. But he checked the RAM one stick at a time, wiggled cables and removed, re-inserted power plugs and such.

So I sent him an old Radeon VT 4350 PCIE 512MB video card that I had. And it booted off of this card. This is a very small cheap card with no extra VGA power ports from the PSU. The card that he was running was a Radeon 6950, that needs the VGA power from the PSU. So I bought him an XFX Radeon RX 580 from Amazon. He plugged this in and again no POST. At this time he is familiar with the beep codes and is getting one long beep indicating "no video card".

He noted that there is a red LED on the new GPU that comes on when plugged into the PCIe slot and a blue LED that is on when the VGA connector is plugged into the card. I sent him a cheap PSU tester that said it looked good but I don't know if it reads all three +12 volt power pin-outs on the VGA cable from the PSU. So I have sent him a multi-meter so he can read all the VGA pin-outs under load and see if it looks funny. He'll get this Monday.

Here are the current Specs:
Motherboard: GIGABYTE GA-870A-UD3
CPU: AMD Phenom II X4 955 Black Edition 3.2GHz AM3
PSU: EVGA SuperNOVA 650 G1, 80+ GOLD 650W
GPU: XFX AMD Radeon HD 6950
RAM: CORSAIR Vengeance 8GB (2 x 4GB)
OS: Window 10/64

So, if the multi-meter read good on the GVA cable under load then it has to be the motherboard, right?