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- cmos checksum invalid

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08-15-2024 07:22 PM
Can someone tell how to fix cmos checksum invalid,cmosreset(502), i installed a new battery in my laptop , but computer won,t load up unless i attach ac adapter to my laptop then i get the message that is above
thanks KINGPIN300800
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Accepted Solutions
08-26-2024 07:38 PM
Hi Alden4,
i resolve my issue with the cmos checksum error. i removed the internal main battery because i didn,t have a cmos battery. then i held down the power button for 15 seconds and then put battery back in and then plugged in the ac adapter and turned on computer. the computer booted up correctly. basically a hard reset. it also solved my problem with having to keep adapter plugged in to computer to startup,now i can just use battery to startup. just thought you would like to know. thanks for all your help.
KINGPIN300800
08-19-2024 06:46 AM
Hi @kingpin300800,
Welcome to HP Support Community.
Thank you for posting your query, I will be glad to help you.
The “CMOS Checksum Invalid” error typically indicates that the CMOS battery is either not functioning correctly or has not been properly installed. This battery powers the real-time clock and stores BIOS settings. Here’s how you can troubleshoot and fix this issue.
Check CMOS Battery Installation
- Ensure Proper Installation: Make sure the CMOS battery is installed correctly. It should be properly seated in its slot, with the positive (+) side facing up if it's a coin-cell battery.
Replace the CMOS Battery
- Battery Type: Verify that you have the correct type of CMOS battery for your laptop. Common types include CR2032 or CR2025.
- Try a New Battery: Even if you just installed a new one, try a different new battery to ensure it’s not a faulty one.
Reset BIOS Settings
- Enter BIOS/UEFI: Power on the laptop and immediately press the key to enter the BIOS/UEFI settings (usually F2, F10, F12, or ESC depending on the manufacturer).
- Load Defaults: Look for an option to “Load Default Settings” or “Optimized Defaults” and select it. Save and exit BIOS.
Power Cycle the Laptop
- Remove Power Sources: Disconnect the AC adapter and remove the battery (if removable).
- Press and Hold Power Button: Press and hold the power button for about 15-20 seconds to discharge any residual power.
- Reconnect Battery and Power: Reinstall the battery and reconnect the AC adapter. Power on the laptop.
Check for BIOS Updates
- Manufacturer’s Website: Visit the HP support website and check if there’s a BIOS update available for your laptop model. Follow the instructions provided by HP to update the BIOS if needed.
Inspect for Physical Damage
- Battery Compartment: Check for any signs of damage or corrosion in the CMOS battery compartment.
- Motherboard: Inspect the motherboard for any visible signs of damage that might be affecting the CMOS battery or its connections.
By following these steps, you should be able to resolve the “CMOS Checksum Invalid” error and get your laptop working properly.
I hope this helps.
Take care and have a good day.
Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping!
Alden4
HP Support
HP Support Community Moderator
08-19-2024 08:10 PM
Alden4,
my laptop doesn,t have a separate battery for the cmos, it uses the main battery.i have tried the solutions that you recommened, but nothing seems to work, if you can think of any other solutions please let me know
Thanks KINGPIN300800
08-20-2024 01:43 PM
Hi @kingpin300800,
Thank you for your response,
I'm sending a private message to assist you with the next action.
Please check your Private message icon on the upper right corner of your HP Community profile Next, to your profile Name, you should see a little blue envelope, please click on it or simply click on this link.
I hope this helps! Keep me posted.
Alden4
HP Support
HP Support Community Moderator
08-26-2024 07:38 PM
Hi Alden4,
i resolve my issue with the cmos checksum error. i removed the internal main battery because i didn,t have a cmos battery. then i held down the power button for 15 seconds and then put battery back in and then plugged in the ac adapter and turned on computer. the computer booted up correctly. basically a hard reset. it also solved my problem with having to keep adapter plugged in to computer to startup,now i can just use battery to startup. just thought you would like to know. thanks for all your help.
KINGPIN300800