HP Omen - Intermittent Power-On / CMOS Error / No Startup

[DanLeeMim]

Looking for help diagnosing a boot/power up issue with my HP desktop PC please! This is a link to my exact computer/specs. HP Omen 25L GT12-1xxx. The motherboard appears to be an Oasis 25L RKL-S Z590H.

The problem started a couple months ago but has been significantly worsening in recent days.

Whenever I press the power button to turn my PC on, it usually comes up with the 'HP OMEN' symbol and then logs me into Windows. Recently, whenever I press the power button, the computer lights up and seems to run, but no feed comes through to my monitor (the issue is not the monitor itself) - my monitor initially brightens a little, then goes into power saving mode. I then have to unplug my computer, plug it back in, and try again - sometimes as much as 7-8 times, before the usual 'HP OMEN' symbol comes back and logs me in as normal.

• Sometimes when it lights up and does nothing, I try to reset it by holding the power button but nothing happens (even when I hold it in for 60+ seconds).
• Sometimes when I unplug then plug it back in, it instantly turns on without me pressing the power button.
• I've done the hard reset route of unplugging and holding the power button - issue persists.
• Sometimes when I unplug then plug it back in, it will start up, then restart itself (without me pressing anything) and it goes to a "CMOS Reset (502)" screen, saying the CMOS checksum is invalid. At this point, I have the option to restart the computer and then the 'HP OMEN' sign loads normally and I get into Windows.

Today however, I pressed the Power button around 15+ times and it was completely unresponsive. I had to keep unplugging/plugging back in, hold the power button in, press it several times - eventually through a combination of these it lit up and came on. 

I've no idea what the problem could be. ChatGPT suggested the CR2032 battery needing replaced, but annoyingly this is hidden underneath my graphics card so I'll have to go to a friend to help me remove it (I'm not techy). 

But could the CR2032 also be the reason for the other power issues above? I'm worried that it eventually stops responding altogether and dies completely.

Thanks for your help.

[Bill_To]

Greetings @DanLeeMim 

Yes, you should probably replace the CR2032 MB battery ASAP. CR2032 MB batteries can last up to four or five years depending on PC uptime.

Consistent PC uptime equals longer CR2032 MB battery life.

It would also be a good idea to check for a recent HP BIOS update only if replacing the CR2032 MB battery does not fix the problem. Go Here.

Input your PC's product number or serial number to check for the latest BIOS update.

Download and install the latest BIOS update. 

BIOS updates are generally safe. But, be patient. Don't turn off the PC during a BIOS update. And loss of AC power during a BIOS update will corrupt the BIOS.

Let the Forum know how it goes.

There is an outside chance your PC's MB has an RTC problem if you continue to experience PC startup problems and CMOS reset problems after replacing the MB battery and updating the BIOS.

Regards

[DanLeeMim]

Hi, I replaced the CR2032 battery this evening, but the issue persists. The clock on my PC has changed to to around 22.5hours in the past.

I checked the link you issued and my HP BIOS is up to date. 

Still having the issue where nothing is happening when pressing the power button. I have to unplug / plug it back in several times, and eventually when I plug in, it'll fire up (without pressing the power button sometimes). Then it'll reset itself, and that's when the CMOS Checksum screen comes up and allows me to restart, which then always takes me to the normal Windows login - but that's the only route that allows me to log in to Windows as normal.

[Bill_To]

Greetings @DanLeeMim 

Sorry to see changing the CR2032 MB battery did not help. This suggests something else is going on.

It sounds like your PC has a MB RTC problem. The repetitive CMOS reset error usually means the RTC is not retaining environment variables required for a good POST. 

And/or a possible power supply problem. Or an additional MB power delivery problem could be indicated since you have to disconnect/reconnect the PC from/to AC power to energize the MB.

Plus the PC intermittently starts up without depressing the power button. This is not a good thing to see.

You may have to have a local PC Tech take a look.

It is not possible to zero in on what's causing this type of hardware problem in a Forum.

Regards