PC goes to sleep (S3 mode) well, but then it's unwakeable

[przemek211]

I used to shut down my PC oftenly with sleep mode (S3 state) for few years. But by now, I can't wake up my PC by wireless key+mice and if I try to start it by power button it starts fans and LED, but PC is dead and I need to reset BIOS by clearing cmos jumper.

I've changed a battery in motherboard, but it didn't help. I've checked if it's something with OS, but the problem occurs also in clear Win10 installation and in Linux live-cd. I've changed in BIOS sleep mode for S1 to check if it's working well - it is, but of course I prefer S3.

I'm not sure why it's caused, but I guess it has to be someting with motherboard. I use GA-946-S3.
Do you have any ideas how can I solve it?

 

[DRagor]

I would rather suspect PSU failing out of specification, especially if it is as old as rest of system. Plus, testing different PSU is much easier then swapping motherboard (and definitely easier to borrow PSU for a test then a matching motherboard). If test with different PSU won't remove problem. then motherboard is next suspect.

 

[przemek211]

I would rather suspect PSU failing out of specification, especially if it is as old as rest of system. Plus, testing different PSU is much easier then swapping motherboard (and definitely easier to borrow PSU for a test then a matching motherboard). If test with different PSU won't remove problem. then motherboard is next suspect.

Thanks for your answer. MB is 8 years old, PSU has 7 yr. I don't have any to test, but I think I can get it tomorrow. Hovewer, before that, I need to tell little bit more. Few weeks ago the problem has started by nightly dead wakeups. I was shutting down my computer with sleep mode, but then, through every next night, PC was waking up and didn't react for anything too. I've done some tests "sleep-wake, sleep-wake..." and PC was waking up well for two-three times, then it was starting to immediate dead wake-up. I've changed the MB's battery and it helped for few weeks until now. Sadly, as I said in first post, next battery change doesn't helps.
So I'll try another PSU tomorrow.

 

[DRagor]

When swapping old battery, have you checked if it not leaked? 8 years old battery could do that, and cause the battery socket to not work well, despite using new battery.

 

[przemek211]

...

No, the battery or socket don't look like anything has leaked. Also, I've checked the voltage between MB & battery and looks like it's as it should (3,29V).
I've tried now to disconnect any unnecessary energy receivers like additional FANs, PCI cards, second HDD etc., but it didn't help.

 

[przemek211]

(...)

You were right Today, I've gotten another PSU and I've done many tests - S3 sleep state works well.
Also, I've recalled that I have this nice PSU (Chieftec GPS-400AA-101A) for seven years, but I bought it as used.
I would never suspect the PSU, because I thought that problems could show when it's under high load, rather.
Thanks for your help, however, I'm little bit scared, because few weeks ago, battery change has helped, so what if I'll buy new PSU and it will work only for quick time

 

[przemek211]

I would just like to add that I've taken a look-see inside of PSU and it turns out that one of capacitor (condenser) has raised: https://i.imgur.com/b0kjaSU.jpg
So, I've changed him to another new one and S3 mode works perfectly again
Thank you very much DRagor because it was really important to put my eyes into PSU instead of motherboard.