Hp Envy 360 17.3 will not start after running a BIOS boot bitlocker suspended

[Bravin99]

I changed the motherboard of my Hp Envy 360 17.3 inch . It worked but kept on bringing the CMOS(502 ) error message. I thought the battery was fine because it was not being read correctly by the laptop 

I suspended bitlocker and tried to reboot but then now I try to start it and gives same error message even if the battery is out only using the AC adapter but goes off after like 10 seconds 

[Kuroi_Kenshi]

Hi @Bravin99,

Welcome to the HP Support Community!

Thanks for reaching out!

We're thrilled to have the opportunity to assist you and provide a solution.

I understand your HP Envy x360 17.3-inch will not stay powered on after a motherboard replacement and a BIOS boot while BitLocker was suspended, and you are seeing a CMOS 502 error with the system shutting down after about 10 seconds. Let’s go through a few steps to check what could be causing this.

Perform a hard reset
This clears residual power and resets embedded controller states after hardware changes.
• Disconnect the AC adapter and remove the battery (if removable).
• Press and hold the Power button for 15–20 seconds, then reconnect only the AC adapter and try to power on.

Check CMOS / RTC battery connection
A CMOS 502 error after a motherboard change often means the RTC battery is missing, loose, or incompatible.
• Open the system and confirm the CMOS/RTC coin-cell battery is present and firmly connected.
• If reused from the old board, replace it with a new compatible RTC battery.

Reseat critical internal components
A loose connection can cause immediate power-off behavior.
• Reseat the RAM modules and try booting with one stick at a time.
• Reseat the SSD and any ribbon cables connected to the motherboard.

Restore BIOS defaults
This helps after a motherboard swap where firmware settings may not match the hardware.
• Power on and repeatedly press F10 to enter BIOS (if it stays on long enough).
• Choose Load Setup Defaults, save, and exit.
• If you cannot enter BIOS, proceed to the next step.

Update or recover the BIOS
A mismatch between the motherboard firmware and system configuration can cause shutdowns.
• On another PC, download the latest BIOS for your exact Envy x360 17.3 model from HP.
• Create a BIOS recovery USB.
• Insert the USB, then press Windows + B, hold them, and press Power to attempt BIOS recovery.

Check power behavior without the main battery
Since it shuts down even on AC, this points away from the main battery and toward firmware or board power control.
• Confirm the AC adapter wattage matches HP requirements for this model.
• Try another known-good HP adapter if available.

I hope this helps.

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