PC not booting - BIOS code 01 boot loop

[theukmoog]

PC is an i7-8700K in a Gigabyte Z370 Gaming 7 motherboard with 2 x 8GB 3200MHz DDR4.

It has been running perfectly since buying it all from OcUK back in June 2018.

It has been switched off for the last 8 days whilst I was away on business.

Came home tonight and it won't boot.

It's stuck in a boot loop, hanging on display code 01 on the motherboard LED before powering off and starting again. In addition, the DRAM status light above the LED display goes on and stays on.

I've reseated the RAM.
I've tried each stick singly.
I've even swapped it for 2 identical sticks from another PC.

The only time it behaves differently is with no RAM, then it hits code 01 much quicker.

Trouble is, I can't find code 01 in the manual or on the gigabyte site or by googling the issue.

I've stripped the PC down to mobo + CPU + RAM, unplugged all drives.

I've tried with the PSU from the other PC, it's only a 500W but I've left the 1080ti out, so 500W should be more than enough).

I've reset the CMOS with the reset button on the motherboard and by removing the power and battery for 10m.

I guess tomorrow I'll take the whole thing out of the case and try it on the desk.

Any other ideas?

 

[theukmoog]

Well, now you mention it, is this a 01 or a D1...

It looks like a 0 to me but what would a D look like on such a LED display?

Anyway, I spent 24h attempting to diagnose it... changing RAM, changing PSU, reseating the CPU... nothing changed!

I gambled on the CPU light going on and then off to mean that the CPU was ok, so I bought a Gigabyte Z390 Ultra, swapped the CPU and RAM over and... it's up and running!

I can only assume that the DRAM light indicated that the memory controller, or similar, had died.