Question Random power loss and immediate restoration (another one!)

Apr 12, 2021
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Hi all, seems that there are a few other people having similar problems to me, thought I'd add my own thread rather than confuse or hijack someone else's!

I have a seemingly random issue where the power is completely cut from my system (as though you'd flicked the power switch on the PSU) an then restored a couple of seconds later - and the motherboard powers back on and the systems boots to the Windows logon screen. I have a Corsair PSU, and I noticed that the other people having similar issues did too - although of course they will likely be popular PSUs so it is probably just that. My system:

Corsair SF750 PSU (plugged into surge-protected 8-gang trailing adapter)
Maximus Gene VII + i7-4790k (not OC'd)
32GB Crucial RAM (not OC'd)
Samsung NVMe SSD (system drive)
3 x WD Red storage drives
RTX 2060 (Pailt StormX)
Asus Xonar PCI-E soundcard

I put this system together in Feb 2019, previously had an ancient CM Silent Pro 700 PSU and an H87 based board which never saw these problems (ironically I changed PSU because I read everywhere that the CM was known to be bad and might be a ticking time-bomb...). Since 2019 I have changed a few things, but this problem has always happened before and after these changes:

1050ti StormX -> 2060 StormX
16GB Crucual RAM -> 32GB
960 EVO SSD -> 980 PRO (I know this is completely superflouous for my system, but I felt like an update and wanted to future proof :p)
PSU power cable changed from old Seasonic braided -> standard cable that came with SF750

From what I can tell my power requirements are well within the 750W limit of my PSU, plus I read somewhere on this forum that it can go to 900+W before giving up, so it shouldn't be overloaded. Also I can report that the fan doesn't spin beyond power-up when it does so briefly. Nothing else attached to the same trailing power adapter sees any problems, and it only has a few other things plugged into it (nothing major).

I've never seen anything in the event logs etc. other than "the previous shutdown at dd/mm/yyyy hh🇲🇲ss was unexpected" and this usually happens under minimal load (only firefox with <10 tabs open and simple browsing). I've never noticed a pattern in terms of when it happens. I have HD Sentinal running as a service and it has a green tick for all of my drives - plus drive, CPU and GPU temps are all good. These power cut-outs worry me mainly because I have some Veracrypt containers that I use for email etc. and I've had a few warnings regarding corruption as they weren't safely dismounted (lost my email program profile more than once). I have backups, but it is still a pain.

Is it significant that the motherboard boots back up again straight afterwards? I don't want to try it but from experience I'd expect this not to happen if I pulled the power cord and plugged it back in?

One last thing - might seem odd having the mobo + CPU combo I do if I'm not overclocking, but I just wanted the best setup possible on Intel 4th Gen so I can stay on Windows 8.1 until it dies (don't want to get into a debate about Win10, I'm just not a big fan of it). Got the Maximus Gene because I have a micro-ATX case (Silverstone TJ08-E) and I wanted a decent amount of SATA ports. But I did have stability problems at first, and these very forums helped me realise that the Maximus Gene overclocks by default (I think?) and I solved my problems by reducing my voltages (as per https://rog.asus.com/forum/showthread.php?51087-Maximus-VII-Hero-4790K-Temps-and-Voltages-Help). They were different problems too - they were as if someone pressed the reset switch on the board/case, as opposed to a complete cut of power. But I realise it could still be board related.

Any thoughts or advice would be much appreciated!
 

Vic 40

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Just look maybe it is this.

Other hing might be "" Asus Antisurge" can disable it in the bios, see if that helps. This is an Asus protection that shuts the pc down when voltages go out of spec, but it can be wrong.
 
Apr 12, 2021
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Just look maybe it is this.

Other hing might be "" Asus Antisurge" can disable it in the bios, see if that helps. This is an Asus protection that shuts the pc down when voltages go out of spec, but it can be wrong.
Luckily I had the box to the PSU handy, as the TJ08-E isn't very helpful for seeing the side of the PSU - as suspected my code (which starts with 184548) is not in the affected range:
We wish to reiterate that only SF Series PSUs in lot codes 194448xx to 201148xx, manufactured between October 2019 and March 2020, are potentially affected. All SF-series PSUs purchased before October 2019 are not affected.
One thing I do wonder about is the length of the modular cables - I previously bought an RM750i, but stupidly didn't realise how long it was and that it wouldn't fit into my TJ08-E as I have an ODD 🤦‍♂️
I realised my mistake and then bought the SF750 which fits perfectly, but the cables weren't long enough - once again 🤦‍♂️ because of course SFX PSUs are designed for smaller cases and I didn't think about it. But then I read that Corsair PSU cables are compatible with each other, and I was able to use the cables from my RM750i. I thought I did some reading around how that should be okay at the time, but maybe the SF750 doesn't like the longer cables?

Will check on the Asus Antisurge, thanks!
 
But then I read that Corsair PSU cables are compatible with each other, and I was able to use the cables from my RM750i. I thought I did some reading around how that should be okay at the time, but maybe the SF750 doesn't like the longer cables?
You should not use modular cables from a different PSU. You can damage/kill your hardware this way.
Even modular cables from same manufacturer different PSU models are not guarantied to be compatible.
 
Apr 12, 2021
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You should not use modular cables from a different PSU. You can damage/kill your hardware this way.
Even modular cables from same manufacturer different PSU models are not guarantied to be compatible.
I'm sure I read at the time that it was an option. Their site seems to suggest that the cables are compatible: https://www.corsair.com/us/en/psu-cable-compatibility
Few people here say it has worked for them, although I guess Reddit users aren't an authority! https://www.reddit.com/r/sffpc/comments/j4bf44 View: https://www.reddit.com/r/sffpc/comments/j4bf44/modular_psu_cables_mixing_corsair_rmx_sf/
 
Apr 12, 2021
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If i'm reading right should the longer cables fit,
https://www.corsair.com/us/en/psu-cable-compatibility

Would look at antisurge.
Thank you, I finally got into the BIOS (fast boot or whatever was making it impossible, even though I saw the prompt and mashed the F2 and DEL keys!) and saw that "Anti-surge support" was enabled so I've disabled it. I also noticed that the "Restore AC on Power Loss" was set to "Power off", which means it should stay off when power is restored following a power failure - so something is definitely deliberately starting the system again.

Will see how it goes!

If I can't solve the problems then I might have to move to a bigger case and use my RM750i instead to compare - shame though, I do really like the TJ08-E and there aren't many compact cases with an ODD slot around these days.

EDIT - just did an image search for Asus Anti-surge and it looks like it gives you a message when it triggers, which I don't see.... unless fast-boot was hiding that as well!
 

Vic 40

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Can look at SFX psu's that come with an ATX bracket like the SF series from Corsair or the Cooler Master SFX gold series, there are more brands with these .

Yeah didn't see you talk about the message, but one can hope.
 
Apr 12, 2021
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Thanks again for the help and thoughts, even if it isn't the Anti-surge it has been useful finding out about it, had never heard of it before!
Can look at SFX psu's that come with an ATX bracket like the SF series from Corsair or the Cooler Master SFX gold series, there are more brands with these .
I do have the Corsair SF750 which came with an ATX bracket, apart from the cable length it is perfect for the TJ08-E and I've generally been very happy with it - aside from the possibility that it is causing these power cut-outs of course.

Maybe I should upgrade the 8-way adapter to a UPS or something... or to start with I could bypass it and plug my PC straight into a wall socket. Might try that.
 
Apr 12, 2021
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Happened again this morning with the PSU power cord plugged directly into the wall and Asus anti-surge disabled. Event 41, unexpected shutdown. I wasn't even in the room using my PC, Firefox was open but that was it. Came in 5 mins later to the login screen.

I've looked up some UPS stuff and whilst it might be way more than I need, I'm thinking of getting an APC UPS with AVR just to rule out the electricity being dodgy - although I never saw these issues in 5 years of living in this house before changing to this particular PSU / mobo / CPU setup. Still, we have done some home improvements over time which has added to the load on the consumer unit. I have been wondering whether we should change our RCDs to be type A (they have always been type AC since we moved in)...

If it still happens with the UPS in place, I guess it is time to start again and swallow the Win10 blue pill...
 

Vic 40

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Think if the motherboard reads voltages wrong an UPS wil not help. Could well be that it still shuts down for unexpected voltage drop, even when Antisurge was disabled.

Can do this, maybe it will show something,

How to make a log,

download hwinfo64,
install and open it,
check "sensors-only",
click "run",
at the bottom of the window click "logging start",
choose a name and place for the log like "hwinfolog" at the "desktop",
this log can be viewed/opened with either excel from Microsoft or libre office calc.
you can upload it onto a site which facilitates this like SaberCatHost this one i like since not so much (or any) spam comes with it and does not require a log in to get the info.
Just make one until this happens like you described.
 
Apr 12, 2021
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Think if the motherboard reads voltages wrong an UPS wil not help. Could well be that it still shuts down for unexpected voltage drop, even when Antisurge was disabled.

Can do this, maybe it will show something,

How to make a log,


you can upload it onto a site which facilitates this like SaberCatHost this one i like since not so much (or any) spam comes with it and does not require a log in to get the info.
Just make one until this happens like you described.
Thanks, that's great! I wasn't aware of this tool - I've got it logging now, at least if the crash happens again then this might help!
 
Apr 12, 2021
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Okay, just see if you want to look at it yourself, libre office calc is freeware,or share here, will look then when i have the time.
Well, it finally happened again! Been a long time, had HWINFO running and now plugged into an APC UPS with AVR which has reported no problems so it really shouldn't be anything to do with my AC supply. One thing that has been interesting is seeing in APC Powerchute that my system draws ~70W when idle, that is lower than I expected.

Here is the CSV: https://wormhole.app/wdR6N#H7friONNE1w4o3oLeScevQ

There's a lot of data in there, I can't see anything at first glance which looks suspect right before the power-off but then again I don't know what I'm looking for!!

EDIT - should have said - system had been on for about 3-4 hours at that point, was idle (I wasn't even in the room) and had Firefox and maybe Thunderbird open.

Would really appreciate any insights, and thanks again for your help with this!
 
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You didn't really stress it and see for now nothing unusual. Will look further, but somehow guess that Antisurge is responsible. Still have the old psu to test with?
Thanks for taking a look! I do have the RM750i in a box somewhere, not very easy to test in my TJ08-E as the PSU is too long (which is why I got the SF750). I guess I could give it a try, will probably have to to solve this.

Re: Anti-surge, I have this disabled and also the default is not to restore power on AC loss/restore. If it was Anti-surge, I believe I would see this kind of message (which I don't)? View: https://imgur.com/KieiL5s
 

helper800

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I would also check all connections from the PSU to the hardware, small for factor builds tend to have issues with cables that are not perfectly the right length. What I mean by that is if the cables are just barely long enough the constant expansions and contractions from heat can loosen them over time to the point that they are in a state that one more contraction and its no longer plugged in, and when it expands again its suddenly plugged in again. Cables that are too long typically just get shoved into wherever they fit in the empty spaces of the case and this can put an unexpected amount of force on the terminals.

TL;DR its worth a check before you rip out the old PSU if you didn't already check all the connections.
 

Vic 40

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Can test with the RMi outside the case, needs to be done wit the sidepanel off and fan up so it can breath, just connect all necessary cables to what you need.

Yeah i'm aware of the message, but right now cannot think of anything else.
 

helper800

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Thanks for taking a look! I do have the RM750i in a box somewhere, not very easy to test in my TJ08-E as the PSU is too long (which is why I got the SF750). I guess I could give it a try, will probably have to to solve this.

Re: Anti-surge, I have this disabled and also the default is not to restore power on AC loss/restore. If it was Anti-surge, I believe I would see this kind of message (which I don't)? View: https://imgur.com/KieiL5s
Typically you would see that on reboot after a surge with ASUS anti-surge on.
 
Apr 12, 2021
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TL;DR its worth a check before you rip out the old PSU if you didn't already check all the connections.
Thank you, I will do that, is probably the most straightforward thing to do at this point.
Can test with the RMi outside the case, needs to be done wit the sidepanel off and fan up so it can breath, just connect all necessary cables to what you need.
Guess that is the next step after checking current PSU connections! Will have to find the RM750 in the loft!
Typically you would see that on reboot after a surge with ASUS anti-surge on.
Yeah, it really shouldn't be that I don't think - have it disabled, don't see the error plus I now have an APC Back Pro-900 with AVR, so I'd really hope the AC supply is good... unless there can be surges caused by the PSU?
 

helper800

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...unless there can be surges caused by the PSU?
If that or anything like it is happening then the PSU is dead or dying ready to take as much as it can with it. Your problem is more subtle, and intermittent. I highly doubt there is any dirty power getting to your PSU at this point. You tried directly from the wall, with the previous power setup and now with a top of the line UPS and all scenarios had the same issue. It is not impossible, but highly improbable that dirty power is your issue.
 
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