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‎02-25-2025 12:30 PM

HP Recommended
Product: HP EliteBook 840 G1 Notebook PC

Dear, HP 

I'm a a HP Elite Book laptop user for past 5 years i bought a 2nd hand laptop. Actually i don't know the model in the back case it shows HP Elite Book 820 and when I entered my serial number it shows HP Elite Book 840 G1.and the main problem is it's not taking power "CMOS checksum is invalid" so I need to change the CMOS battery so which battery should be replaced "CR2320" ?? When I googled about HP Elite Book 820 i saw "CR2320" suits it..Also I can't find a CMOS CR2320 battery so can I use normal CR2320 Battery available in online?? 

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1 REPLY 1

‎02-25-2025 12:56 PM - edited ‎02-25-2025 12:57 PM

HP Recommended

Hi:

 

Chapter 5, page 64 has the RTC (CMOS) battery part number and description/removal and replacement procedure.

 

c04655205.pdf

 

It is probably a CR2032 coin cell battery with some metal contacts tack-welded to it and covered in a plastic cover.

 

I made one once for a different model PC because I was in a hurry and didn't want to wait to order one.

 

I just carefully took the dead battery apart and got the metal contacts off it and electrical taped the contacts to the CR2032 battery and it worked fine.

 

But if you don't want to do that, then you will have to order the correct part that has the wire terminal.

 

665733-001 for sale | eBay

 

 

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