Pavilion 15 won't boot

[LucaLauro]

Hi,

I think my pc experienced USB overvoltage after the connected microcontroller accidentally shorted with a 12V power supply.

Despite controller pcb and internal USB port protections, PC got damaged in some way:

after pressing the power button and the relative LED lights up, only the fans start at a normal (low) speed but the computer does not boot; I think it does not even perform the entire startup firmware because keyboard backlight doesn't work and the display doesn't get power either.

I have done all rapid hardware tests (hard reset, external monitor, power, battery, ram...) and tried executing the HP diagnostics UEFI from USB stick but nothing (if it doesn't complete the startup routine I cannot access any UEFI tool).

So I suspected a motherboard failure, but there are no visible signs of burned components, all voltage regulators are fine and the USB port power too.

Understanding that there are many other possible hardware causes of boot failure (MOSFETS, various passive components, chipset...), is it possible that the startup firmware on the SPI flash has been corrupted?

Thanks for your time.

[LucaLauro]

Update: I discovered that the day after the accident, following yet another attempt to turn it on, on my Microsoft account a new bitlocker key was created where the device ID was no longer the one I set, but it returned to the original one.

I don't know if I should interpret this as a positive or very negative thing, but if the key on my account has been updated, doesn't it mean that the PC has actually started up and connected to the internet?

[Raj_05]

Hi @LucaLauro,

Welcome to HP Support Community.

Thank you for posting your query, I will be glad to help you.

It sounds like your HP Pavilion 15 laptop experienced a hardware issue due to a USB overvoltage, which may have caused damage at the system board level. The fact that the fans turn on but the laptop doesn't boot, with no display or keyboard backlight, points to a serious failure in the startup process. Your mention of a new BitLocker key being created and associated with the device on your Microsoft account is curious—it could indicate that the laptop briefly attempted to boot or that some form of recovery was triggered by the system, even if the boot process wasn't visible to you.

Here are a few key considerations and troubleshooting paths.
 

SPI Flash Corruption Possibility

The SPI (Serial Peripheral Interface) flash on the motherboard is where the BIOS/UEFI firmware is stored. If this firmware has been corrupted, the system could indeed fail to complete the boot sequence. However, SPI flash corruption is relatively rare, but it's worth considering, especially since your device doesn't seem to get far enough to even initialize external displays or keyboard backlights.

If you suspect SPI flash corruption, here are potential next steps:

• BIOS Recovery Attempt: On some HP laptops, holding down specific keys while powering on the device (e.g., pressing Windows Key + B or V and then powering on) can trigger a BIOS recovery from an internal backup or a USB device.
• Flashing BIOS via USB: If your laptop supports it, you might be able to recover or re-flash the BIOS using an external USB with a BIOS update file from HP's support website.

BitLocker Key Change

The creation of a new BitLocker key suggests that the system may have tried to boot but encountered an issue that triggered a reset or re-encryption event. This might happen if there was a significant hardware change (e.g., a motherboard component failure or corruption that caused the system to believe a new configuration was in place). However, since the system doesn't boot visibly, it's possible the attempt was incomplete or intermittent.

• Positive Interpretation: It could mean the laptop started up at least partially at some point and connected to the internet. The change in BitLocker key might suggest that the system reset itself or detected a hardware change.
• Negative Interpretation: The key change might also indicate that the system reset important hardware identifiers or experienced a significant issue that led to reinitialization of encryption without completing a full boot process.

Motherboard Diagnosis

Given that no visible damage is present on the motherboard and the power components seem functional (e.g., voltage regulators), the problem could be with the MOSFETs, chipset, or other sensitive components on the motherboard. 

If a hardware failure has occurred, especially at the chipset or CPU level, you may need to replace the motherboard. The overvoltage from the USB port might have damaged critical components that are not easily identifiable without more advanced testing.

Next Steps and Recommendations

• BIOS Recovery: Try the Windows Key + B (or V) method to see if a BIOS recovery is possible. You can also try a USB BIOS recovery if the laptop supports it.

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 

[LucaLauro]

Thanks for your attention,

I have already tried the various possible combinations for bios recovery but nothing worked (I think the keyboard is not initialized at all, which is a big clue).
Fortunately the ssd does not seem to have suffered any damage, so I managed to recover all the data with the normal bitlocker key (not the one that was automatically created, strangely).
Moving on to the motherboard, the microcontroller I had connected included an overcurrent protection, so it probably suffered "only" damage from overvoltage (semiconductors mainly).
I checked better and found voltage regulators of the chipset damaged: the chipset is not powered.
I will send it for repair hoping that there is no more serious damage and will update the post with the results hoping that it can also be useful to other users.

thanks for the great reply and have a nice day.

[Raj_05]

Hi @LucaLauro,

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