NUC7 auto starts after plugging in. Shows CMOS Battery Failure

[darbid]

If I unplug my NUC7i5BNH (with Board NUC7i5BNB) and then plug it back in then it auto starts. It then shuts down. Starts again. Shuts down. Starts again and shows warnings

CMOS Battery Failure

CMOS Checksum Error

CMOS Tiem Not Set

Things I have tried;

I have replaced the battery. No Change.

I have recovered the BIOS to BNKBL357.86A.0083.22020.0714.1344.  No Change.

What else should I do?

[n_scott_pearson]

This is actually perfectly normal if you've just replaced the battery. You need to use F2 to enter BIOS Setup (Visual BIOS). Once there, use F9 (followed by Y) to reset the BIOS configuration, set the date and time and then user F10 (followed by Y) to save this configuration and exit. After it goes through POST, you can again use F2 to enter BIOS Setup and configure the BIOS as needed for per your hardware, OS configuration and preferences.

Hope this helps,

...S

[darbid]

Thank you for picking up my question and the clear instructions.  I did a F9 reset and set the clock.  I then let it post again.  I then turned off the NUC and pulled out the plug.  Upon plugging it back in again it started automatically again (actually starts a stops a couple of times) and shows the same warning messages.

The only other thing I notice is that my clock settings are not being kept which means to me that there is a battery problem.  As the battery is, however, new, I assume there is some other problem.

Are there any tests I can do or something to narrow down what is happening?

[LeonWaksman]

1. Verify that the CMOS battery connector if firmly inserted. Clean the contact using contact cleaner spray.

2. Verify the correct voltage (use DVM) on the battery connector. Even the battery is new it doesn't proof that it is still supplying correct voltage 3.3 V

Leon

[n_scott_pearson · Accepted solution]

You also need to verify that the replacement battery is wired correctly. A great many of the batteries for sale are wired the opposite way.

...S

[darbid]

The replacement battery was not wired correctly.  Change the wires around did a F9 reset and it now is back up and working.

Thank you everyone

[n_scott_pearson]

Good to know. Enjoy!

...S