My notebook wont turn on until plugged in and CMOS 502 error on every startup.

[Orlog]

It all started when the original battery gave up soul. The machine then gave me a CMOS RESET 502 error every time I started. At first I thought the CMOS battery was the problem, except I couldn't find it on the Motherboard. After I tested my main battery and it was really bad so I changed it for a new battery that works very well. Except that every time it completely discharge or the machine is turned off for more than 10 minutes, I get the CMOS Rest 502 error on startup. And that's not all, the machine refuses to turn on if it is not plugged in, regardless of the level of the battery. I have to connect the power supply if only for a few seconds before it turns on. And then I can unplug without problem until I turn off the machine again or the machine is discharged. I updated the BIOS, restored the default settings, calibrated the battery, without success, I tried everything on the forums here and elsewhere without success. My warranty has already expired and I cannot go to a repair center, what should I do? 

[Echo_Lake]

@Orlog

Thank you for posting on HP Support Community.

Don't worry as I'll be glad to help, I understand that you are getting a CMOS 502 error on your HP notebook. I have a few troubleshooting steps we could try to fix the issue:  

1. Turn off the computer and wait five seconds.

2. Turn on the computer.

3. When the first screen displays, do one of the following:

   • Immediately press the F10 key repeatedly, about once every second, until the Computer Setup program opens.

   • Immediately press the Escape key repeatedly, about once every second, until the Startup menu opens. Then press F10 to open the Computer Setup program.

4. In the BIOS Setup utility, select the File tab.

5. Select Apply Defaults and Exit.

   Figure : Setting the defaults

   

   The computer restarts.

   If the error no longer appears, you are done.

   If the error appears, continue using these steps.

6. Replace the battery on the motherboard.

7. After replacing the battery, restart the computer to see if the error continues.

   If the error no longer appears, wait until Windows opens and set the date and time to current settings.

And, also you can refer to the article: HP Notebook PCs - Recovering the BIOS (Basic Input Output System)
 

Hope this helps! Keep me posted for further assistance.
Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.

[Orlog]

I've already done all these steps , but the problem still there.

[Echo_Lake]

@Orlog

Thank you for posting back. 

Its sounds like hardware related issue with the Notebook. As we have limited support boundaries in the support community as of now.

I would request you to contact our Support and our Support Engineers should be able to sort this out. HP Support can be reached by clicking on the following link:  www.hp.com/contacthp/

Please feel free to contact us here anytime you need any further assistance. Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.