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- HP Community
- Notebooks
- Notebook Boot and Lockup
- Re: PC is constantly showing CMoS error 502 during startup.

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06-27-2022 12:57 AM
My PC constantly shows CMoS error during startup. I tried several ways to resolve it but nothing worked. Moreover the battery too, despite of being connected to the charger shows discharging. The PC doesn't start if not connected to the charger and the battery constantly shows 7% charging only..
Kindly help in resolving this issue..
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Accepted Solutions
06-27-2022 02:19 AM
Hello @Dev05
Maintenance and Service Guide (the most important documentation)
http://h10032.www1.hp.com/ctg/Manual/c06140017.pdf
(1) Shutdown ( No Sleep or Hibernate ) your notebook
(2) Remove battery
(3) Disconnect power charger
(4) Press and hold power button for 30 seconds
(5) Install battery
(6) Connect power charger
(7) Start and enter BIOS to load setup defaults, save and exit
(8) Shutdown
(9) Start again. Do you still have CMOS error ? Then the internal CMOS 3V (Voltage) battery (CR2032) has to be replaced.
See Maintenance and Service Guide
best regards
---
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make it easier for other people to find this type of solution by marking the reply ▶️ [ Accept as Solution ] ◀️
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06-27-2022 02:19 AM
Hello @Dev05
Maintenance and Service Guide (the most important documentation)
http://h10032.www1.hp.com/ctg/Manual/c06140017.pdf
(1) Shutdown ( No Sleep or Hibernate ) your notebook
(2) Remove battery
(3) Disconnect power charger
(4) Press and hold power button for 30 seconds
(5) Install battery
(6) Connect power charger
(7) Start and enter BIOS to load setup defaults, save and exit
(8) Shutdown
(9) Start again. Do you still have CMOS error ? Then the internal CMOS 3V (Voltage) battery (CR2032) has to be replaced.
See Maintenance and Service Guide
best regards
---
Dear Community Member, please click the button [ YES ] on "Was this reply helpful?" to say Thanks and
make it easier for other people to find this type of solution by marking the reply ▶️ [ Accept as Solution ] ◀️
Do this on the post I wrote that helped solve it.
Thank you very much
⌨️