Question Socket AM4 motherboard won't boot

[FRoob]

Back in August I asked for help because my Asus Prime B450M-A motherboard with a Ryzen 5 3600 CPU had stopped booting for no apparent reason. The original thread is here:

Question - System won't power up

First post here! I have an Asus Prime B450M-A motherboard purchased with a preinstalled Ryzen 5 3600 CPU and stock cooler. It has worked fine for about two years, then one day it would no longer start when I pushed the power button. I suspected the PSU, so replaced that. There was no...

forums.tomshardware.com

System details:

Asus Prime B-450M-A motherboard
32GB RAM (2x16GB modules)
Ryzen 5 3600 CPU
Zotac GeForce GTX 970 GPU 4GB DDR5
C-drive 500GB Crucial SSD connected via SATA 600
Corsair RM750x PSU (brand new as I changed this as the first course of action after the problem started)

This is a 2 year old self-built system (using a pre-assembled motherboard/cpu/RAM combo) used mainly for photo and video editing. No overclocking at all.

Symptoms: After pressing the case power button the power light comes on briefly and the fans spin for a moment and then everything stops. The power button is ineffective after this unless your power cycle from the mains AC.

It turned out, happily for me, that the motherboard, CPU and RAM were still under a 3 year warranty, so I RMA'd the motherboard combo back to the supplier but they tell me it's working perfectly.

I've reinstalled everything and it's still not working.

The only likely suspect I have left is the GPU. If faulty, could this be causing the symptoms described? Unfortunately, I don't have spare GPU on my hands to test this theory.

 

[Lutfij]

The only likely suspect I have left is the GPU. If faulty, could this be causing the symptoms described? Unfortunately, I don't have spare GPU on my hands to test this theory.
This is where you source(borrow) a donor GPU from a friend or neighbor and try it out on your platform or take your GPU to a known working platform.

 

[FRoob]

The only likely suspect I have left is the GPU. If faulty, could this be causing the symptoms described? Unfortunately, I don't have spare GPU on my hands to test this theory.
This is where you source(borrow) a donor GPU from a friend or neighbor and try it out on your platform or take your GPU to a known working platform.

Yes - I'm in th e process of doing this but I live in a remote area and it's not easy. I was mainly wondering what the likelihood would be of the GPU being responsible for thr problem as I haven't found any anecdotes to support the theory.

 

[FRoob]

Well, quite by accident I discovered that it was the DVD rewriter drive that was the culprit. It had remained connected to the PSU all along and only when I disconnected it did the motherboard power up normally. Of all the the things...