HP Laptop 17-cp0001ca boots with "CMOS checksum is invalid" error and clock does not keep time

[Steve_Hanson]

HP Laptop 17-cp0001ca boots with "CMOS checksum is invalid" error message and clock does not keep time when off or sleeping. I cannot find a CMOS battery.  Does the main battery need replacing?

[Paul_Tikkanen]

Hi:

Most likely the main battery will need to be replaced.

Your notebook does not have a CMOS/RTC battery.

The main battery also serves as the CMOS/RTC battery to maintain the BIOS and clock settings.

Chapter 3 of the service manual has no CMOS/RTC battery part number and chapter 5 has no CMOS/RTC battery removal and replacement procedure.

Maintenance and Service Guide (hp.com)

[Steve_Hanson]

s for the suggestion.  I have replaced the main battery, but the problem still persists. It does go to sleep now when I close the lid, which is a huge improvement, but I still get the "CMOS checksum is invalid"error on boot up and the clock remains at the time I close the lid and needs to be reset every time I reopen it. I have tried downloading a new bios but it tells me the bios I have is up to date.

[Paul_Tikkanen]

I wouldn't know what the problem could be if you replaced the battery, and the BIOS is up to date.

It's possible that the CMOS chip has a hardware issue.

I had a HP notebook (255 G7) no RTC battery, where the internal battery was good, fully charged and I still got an occasional CMOS checksum invalid message.

Then one day, it just went away by itself and never came back.