PC lights blinking after shutdow

noj · 4 Jun 2015 at 09:07

I'm running a gigabyte z68x-ud5-b3 mb, and still getting some odd behaviour on the PC.

After shutting down the PC I notice that lights are still blinking on and off, this includes the lights on the USB mic plugged in and, sometimes, the backlighting on the keyboard too.

On the motherboard itself the Power button inside the case and a red LED marked S4-S5 both blink on and off.

The PC powers up ok and runs fine - sometimes though I'll get a warning about voltage levels on a USB port.

According to the manual on the MB the S4-S5 led is a ACPI led warning of an "improper plug/unplug action" (?)

I've gone searching around for solutions but cant find anything that mentions this kind of issue.

Trying to work through the problem I'm thinking its either a PSU problem - its an old PSU (8 years) so maybe there is a voltage problem, or maybe its a problem with the motherboard itself.

I've tried checking all the connections on the PSU and MB to make sure they're sat ok

With money a bit on the tight side at the moment I'm trying to find a cheap way to find the problem.

Any suggestions?

Hodders · 4 Jun 2015 at 10:03

I'm guessing it's a power management thing.

Try turning off the various 'wake on' settings in the BIOS. I'm guessing that your PC turns on when you click a mouse button etc.

russell664 · 4 Jun 2015 at 11:38

I agree with the suggestion about power management Hodders made.

Have a look in your BIOS for 'wake' or power settings.

noj · 4 Jun 2015 at 11:41

The PC wont turn on in that way, and I've made sure its not going to sleep when I power off.

I'll have a look through the bios settings tonight and see....I'm just not sure what the pc is trying to tell me. The MB manual isn't exactly helpful in saying what causes the lights to blink or if they should/shouldn't be.

russell664 · 4 Jun 2015 at 11:42

Generally my lights only flash when in sleep mode.
However, not so much on X79.

Report back once you have had a look in the BIOS.

noj · 4 Jun 2015 at 19:46

i checked through the bios again and nothing there is set to wake the machine up.
I've gone through the power settings in windows as well to see if anything there would be causing it and afaik its all standard stuff - i run on high performance setting with sleep = never

when the machine is running everything seems fine, maybe i'm just being paranoid and should ignore it?

wazza300 · 4 Jun 2015 at 20:58

do you have on/off charge software running? could be that?

noj · 5 Jun 2015 at 08:21

wazza300 said:
do you have on/off charge software running? could be that?

no, well, not that I know of or could find on the machine.

This is why I'm thinking it might be hardware....could it be that the PSU isn't giving enough power to the board after its shutdown and the blinking is a sign of low power?
Or maybe its the psu isn't giving power in a smooth fashion (if that makes sense) so its pulsing which causes the blinking?

wazza300 · 5 Jun 2015 at 15:56

I don't think its that

there used to be an option in one of the gigabyte software to turn off the mb lights,power saving software but that was on x58,not sure if it applies to z68

noj · 5 Jun 2015 at 16:12

I'll have another look when I get home but I'm sure none of it is running. I think I've only go the easytune6 software installed and I've never used that - but worth the look just in case

noj · 8 Jun 2015 at 09:19

I went through the system again at the weekend. I found a bit of software from Gigabyte call on/off charge that was installed.

Uninstalled it, ran CC cleaner to make sure it had gone, rebooted, then powered down - still the same.

If its not going to damage anything then I'll just ignore it (or simply turn off the plug socket).