Computer intermittently won't switch on

[DevPete]

There have been a couple of times where my computer won't switch on. The USB hub lights up when the power is switched on, but when I press the power button, the USB lights go out. It seems to be ok if I switch the power on and off again though.

Any ideas what could cause these symptoms? The power cable doesn't appear to be loose, I had wondered whether it was something like undervoltage protection (my Seasonic PSU has it), or perhaps my surge protector may be having a few issues ? The machine works flawlessly when started (even for gaming).
It's hard to do any diagnoses because it doesn't happen often. The times when it didn't start happened to be colder mornings though, but would have still been at least 18C in the machine.

 

[DevPete]

The components haven't changed for just over a year and the age of the most components is around 4 years.
Seasonic 750W PX750 (just over 1 year old)
CPU AMD 3950X
AMD Radeon RX7900XT (just over 1 year old)
3 SSD's

I would imagine a good 750W PSU would handle that quite easily. The power light doesn't even come on and the PSU relay doesn't even click, so I can't imagine the GPU would be drawing much power at this point.

The difficulty with trying different components is that I may know if it doesn't fix the problem, but won't know if it does fix the problem because the problem doesn't happen every day.

 

[DevPete]

Yes, 750W with a quality Seasonic is enough.



I would recommend turning off fast boot (if enabled) as the 7900xt does have significant initialisation time between the time the power is switched on and the motherboard BIOS initialises/boots. It's an issue reported more on Intel builds but cold boot issues still occur with the 7900XT on full AMD builds.

I would update your motherboard BIOS to the latest release, plus the GPU BIOS - if it has an update (read notes as they mention stability etc...)

I've had cold boot issues with a few builds through the years - BIOS updates and tweaks usually resolved the issue, if it wasn't a hardware fault. I had one build that didn't resolve - but it was a common theme for that particular ASUS board. it was disconcerting but eventually accepted it... kinda.

Thank you. I think fast boot is off (I will check).

I do have one other idea though. The switch on my socket was jamming a bit recently (needs replacing). I'll try moving to my other one and see if I don't get the problem

 

[DevPete]

I think I know what the problem is now. It's probably the simplest thing, but the last thing I thought of . I believe it was the switch on my socket not working.

I've been using a different socket for a while now and had no problems. My phone charger recently failed to work when on the older socket though.