NUC8i7HVk will not boot after disconnected from mains for 3 weeks

[ScottyP]

Due to electrical storms at this location I frequently put this computer in the safe when I am away for an extended period.

This time no response to power button. No LED or fans.

Power brick verified ok.

Disconnected CMOS battery and cables for 15min....no change.

Attempted BIOS revocery/upgrade (ver67) on FATA32 formatted usb drive with security jumper removed.......nil response.

I recently upgraded to Win11 and had no issues.

My BIOS is at version 64 as far as I can remember

During troubleshooting over a few days it booted once spontaneously but was unresponsive.

No signal to monitor so could not change or check anything.

[n_scott_pearson]

Your CMOS battery may be losing its charge. You can purchase a replacement fairly cheaply (I see lots on NewEgg and Amazon and elsewhere). Here's an example: https://www.amazon.com/dp/B08NZVFQRJ. 

Hope this helps,

...S

P.S. Note that some Dell PCs use a battery with the opposite polarity, so make sure that the battery you choose matches connector color positions with the one in your NUC currently.

[Karan1997]

Well, you are true, my friend purchased this **bleep** https://www.amazon.com/dp/B08NZVFQRJ sometime back and now regretting it   

[ScottyP]

Thanks Scott, I had already installed fresh cmos battery with no success.

Fully disassembled computer, cleaned with compressed air.

We live in a maritime atmosphere with humidity over 90% for last 2 months with the floods so I suspected moisture salt and dust.

Unfortunately this did not work.

I left it fully assembled for a week plugged in and then one day as I walked past it was running.

Only thing missing was the PIN to access it.

Everything else running normally.

Odd that it self started.

I have flogged it since then, throwing every test at it and can not produce any faults.

It sleeps, hibernates etc  ie no fault with power button and system suspension/activation.

Thanks, Scotty P