Computer intermittently won't switch on

DevPete

DevPete

DevPete

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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.
 
What's your complete spec and age/spec of the Seasonic?

It's a quality branded PSU but power demand, age, bad luck can all be a factor.

If you're plugged into an extension lead you need to rule that out by plugging directly into the wall (bypass surge protector too). And no harm in trying a new kettle lead if you have one.

That said, have you added any new components lately?

Additional - check boot priority in the BIOS. Make sure your main drive has priority.

Perhaps disable fast boot if selected.
 
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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.
 
Yes, 750W with a quality Seasonic is enough.

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.
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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.
 
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Plec said:
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.
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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 said:
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
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Faulty extension leads can be the cause of power issues, that often get overlooked. But, a faulty mains socket is worth ruling out if you're experiencing issues.

Best of luck - let us know if you find a solution.
 
just because rhw
DevPete said:
I would imagine a good 750W PSU would handle that quite easily.
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Just because the seasonic 7050w PSU should be able to handle the system, does not mean it can if it is broken, or on its way out
seasonic returns are pretty good, try a new PSU to rule that out, and RMA the broken old one if it is that
 
DevPete said:
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.
Click to expand...
My old pc would not always power up, would take a few attempts. I changed the battery on the mainboard and it was OK then.
 
It could be the capacitors taking a little while to energise. When you turn the power on at the wall. Leave it for 10 seconds then switch the computer on.
 
I had this issue in an old pc.
I found a work around for mine hitting the power button, then pressing reset at the right time.

I think the PSU from a cold boot didn't send enough voltage, AFAIK its one of the first things the power on self test of the motherboard does.


For mine I eventually built a new pc and quickly tested my new psu in my old comp and it had no issues at all so must have just been a slightly dodgy PSU
 
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.
 
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