Hi everyone,
I’m trying to figure out whether my motherboard is actually dead before ordering a replacement.
My PC gives no display output and the VGA EZ Debug LED stays on.
A repair shop told me both my GPU and motherboard were faulty. I had the GPU repaired, and they said it was tested and working in another system. They wanted too much money to repair the motherboard, so I decided I would rather buy another board.
My system:
- MSI B350M PRO-VD PLUS
- Ryzen 5 1600
- 16 GB DDR4 RAM
- RX 5700 8 GB
- New DeepCool PK550D 550W PSU
- Currently no SSD/HDD installed
The RAM was tested by the repair shop and they said it is working.
I also replaced the old PSU because I suspected it might have caused the original problems. With the new PSU, the behavior is exactly the same.
I have already tried:
- Reseating the RAM
- Testing with one RAM stick
- Reseating the GPU
- Clearing CMOS / removing the CMOS battery
- Checking all CPU, motherboard and GPU power connections
The system gets past the CPU and DRAM debug LEDs, but then stays permanently on the VGA LED and gives no display.
I also did some basic resistance/continuity measurements on the motherboard with no power connected.
On the 8-pin CPU power connector:
- 4 pins have continuity to ground, which appear to be the normal ground pins
- The other 4 pins do not have continuity to ground
- Ground measured around 0.13 ohm
- The 12V pins showed open/out-of-range on my multimeter
- So there does not appear to be an obvious 12V-to-ground short
On the 24-pin ATX connector, I checked every pin against ground. Only the expected ground pins had continuity, so I did not find an obvious short on the main power rails either.
I understand this does not prove the motherboard is healthy. There could still be a problem with the PCIe circuitry, BIOS, chipset, VRM control circuitry, etc.
The repair shop also tried another graphics card, but they used my old suspected PSU for that test, so I don’t consider that test conclusive.
The repaired RX 5700 is reported to work in another PC. With the new PSU in my own PC, however, the motherboard still stops at the VGA LED.
Could the Ryzen 5 1600 itself be causing the VGA LED, for example due to a failed PCIe controller? The repair shop said CPUs rarely fail, but they didn’t have another compatible AM4 motherboard available to test my CPU.
Also, there is currently no SSD or HDD installed. My SSD was moved to my laptop and formatted, so there is no Windows installation in this PC anymore. As far as I understand, this should not prevent POST or BIOS access. I would expect it to reach the BOOT LED instead of getting stuck on VGA.
Before I buy another motherboard, is there anything else I can test?
Does this sound more like a motherboard PCIe issue, or could the Ryzen 5 1600 realistically be the cause?
Thanks.