HP 15-ef0023dx display freezes on startup

[MikeAndMel]

HP 15-ef0023dx display freezes on startup.  Black screen with HP logo.  I found a way to resolve the issue but it is a workaround.  On startup, I press ESC and then F10 to go to the BIOS.  The BIOS is the latest F.42.  In the security section, I select Restore Security Settings To Factory Defaults.  After putting in the code requested by the action, I exit and save and the boot up sequence works about 90% of the time it makes it all the way to Widows 10..  If not, I just repeat the process.  Later, I started the machine by pressing the windows key and the V key while pressing the power button for 2 to 3 seconds.  The message that follows states the CMOS checksum is bad so I follow the instructions to fix that.  But it doesn't fix the issue.  Generally when there is a CMOS checksum error, a message usually says to replace the CMOS battery.  I can't find a battery for the CMOS, yet.

Has anyone else experienced this issue?

Patrol Captain

[KrazyToad]

@MikeAndMel

Welcome to HP Support Community

I would like to help

I appreciate all your efforts and expertise in troubleshooting this issue

I suggest you contact HP Support and get the CMOS Battery replaced

1) Click on this link - www.hp.com/contacthp/ 
2) Select your product type below.
3) Enter the serial of your device. 
4) Select the country from the drop-down. 
5) Select the chat or get phone number options based on your preferences. 
6) Fill the web-form and proceed further.

Thank you

If the information I've provided was helpful, give us some reinforcement by clicking the "Solution Accepted" on this Post and it will also help other community members with similar issue.
 

[MikeAndMel]

Hi Krazy Toad,

I have a better idea.  I tried all of your suggestions well before I posted my concern.  Since you work for HP Support how about you try to find how to replace the CMOS battery.  Better yet, it would be helpful if you could locate where the CMOS battery is in the laptop.  I had the entire unit opened and was not able to find the battery.  In all the years I've been repairing PCs, I've never seen one without a CMOS battery.  The virtual agent is helpless in this regard because it assumes that the laptop gets through the initial boot up process before loading Windows.  Further, there is no error message stating a CMOS error unless I interrupt the boot process to check the CMOS. 

Anyway, if you can take the time to research to research this issue to find the CMOS battery's location in the laptop, the serial number of the laptop is 5CD0151HP5 and the model number is 15-ef0023dx.  I hope you have better luck than I've had, so far.

Best regards, my friend. 

[KrazyToad]

Unfortunately there are no HP Documents or Manual for this Model showing how to access the CMOS Battery

The CMOS Battery should be on the Motherboard. Since there are no information regarding the CMOS Battery available for this Model, It's recommended to talk to HP Support Engineer in your region and they should be able to walk you through

1) Click on this link - www.hp.com/contacthp/ 
2) Select your product type below.
3) Enter the serial of your device. 
4) Select the country from the drop-down. 
5) Select the chat or get phone number options based on your preferences. 
6) Fill the web-form and proceed further.

Thank you