Corsair HX750i modular faulty? Edit: it was CMOS battery!

Fengxian · 19 Oct 2020 at 20:07

Hello, I think my psu is failing and could do with some suggestions to figure out if it is.

It's powering:
Asus 1070 gpu
Asus prime z390-a motherboard
I9 9900k
3TB green drive
120GB ssd
8 GB Corsair vengeance RAM and 8GB(2x4) vengeance RAM
3 LED strips (can't remember brand)
WiFi card (can't remember brand either)

So here's the problem, pretty much out of nowhere my pc has started to have severe restarting problems, sometimes I can run my pc for an hour with no problems whereas other times it goes into a restart loop that's impossible to get out of. The pc even restarts from the BIOS menu if left alone. All the temperatures are fine, I've used software to check all voltages which seemed fine as well as software for temperatures. I've taken everything out and replaced it several times, alternating ram sticks, with and without the gpu and reseated the CPU as well as all wiring for all components. I've noticed that if I take out the 8GB ram stick that the pc "stays on" for longer but always ends in a restart which progressively gets faster and faster until the pc just turns off. I've searched for possible problems and my only conclusion is the PSU but I wanted some opinions and advice before I RMA and ends up not being the PSU. The PSU is only 6ish years old. Thank you anyone for help or suggestions.

Fengxian · 20 Oct 2020 at 09:50

I'm not overclocking and never have, my mobo does have a built in "optimiser" which it appears can't be turned off anyway. I've used software to monitor temps and voltages and for as long as the pc stays on they have all been within the proper guidelines and no sudden spikes or anything. The problem with trying to use any form of software is the pc no longer stays on long enough to actually do a decent test. I don't have any way of testing my parts in another pc which I know would be really helpful. I'll try the memtest after work and get back to you. Thank you both very much for replying

P.s I didn't check the ram compatibility but I assume it's fine as it's worked for months with no problems, I'll check that too anyway just to rule that out.

Fengxian · 20 Oct 2020 at 14:33

So I got as far as downloading the memtest files before the first restart, read the directions the second time and then another restart. Now my pc does nothing, it turns on and the fans come on for a second then instantly restarts. This is now all my pc does

Fengxian · 20 Oct 2020 at 15:38

mickyflinn said:
Take the gpu out and see if will boot from the onborad, you mite need to clear the cmos.

Did this and still the same thing. I did just notice that when switching the power switch back on it took a fairly long time for the mobo lights to come on, whereas normally they light up as soon as I turn the switch on. More and more I'm thinking this is a PSU issue, it's as if it's slowly degrading.

Already reseated my cpu yesterday as well.

Fengxian · 22 Oct 2020 at 15:30

I really don't want to jinx this, but I thought I would update for anyone looking for a solution to a similar problem.

After trying absolutely everything I could possibly think of, I came across someone posting on another forum about the same MOBO I have. They described exactly the same issues I have and all they did was to simply replace the CMOS battery.

Chucked in a new Energizer battery after work today, pc has turned on first time, got into windows and managed to update some stuff. So far so good! Never in my life of PCs have I ever had a CMOS battery fail and more to the point who would have ever thought it could cause complete system failure issues such as this? Fingers crossed that this was the issue, as frustrating as it's been the past week trying to sort this out, it's definitely a cheap and easy solution. Thank you guys again for trying to help!