5 Capslock flashes, no boot / display on HP Elitebook 850 G8

[momolar]

Hello,

I have 2 motherboards for HP Elitebook 850 G8.

Motherboard model: Corvette-6050A3216701-MB-A01

After trying to remove the BIOS password by reflashing BIOS, the first board fails to boot. I then reflashed the original BIOS / EC back, but no success. I don't know if I damaged the board or if the dumps are bad.
I bought the second motherboard as a replacement but it seems to have same issue somehow.

Curiously, when I try to boot without RAM, I get the expected 3,2 error flash code "missing RAM". Everything is normal until here.

When I boot with RAM, I get a 5 slow capslock flash error code. Which I believe is either failure to POST or system board failure. Yes I have tested different RAM modules. The fan also spins and CPU heats up.

This suggests that the board manages to POST to at least RAM initialisation, but then fails at some point after. Correct?

I have inspected the board, and no components seem damaged. All power rails are good, and I haven't found any shorts. If the board is able to give an error code, that means that the CPU is still working right?

I am completely lost as to what the issue could be. Is it possible that it's simply a bad BIOS issue?
I would have thought a bad BIOS would have fully prevented POST but after reading some posts here it seems like some have had the same issue.

I'm attaching the board schematics for the
Corvette-6050a3217501-Mb-Ax2.
This is for Elitebook 840 G8 motherboard, not 850, but I think all labels are the same and could help. I don't have other schematics.

Will upload the 2 BIOS and EC bins tomorrow if needed.

Can anyone help diagnosing?

Thank you!

[elgollo51]

Good afternoon, please, someone who has an HP 850 G5 mainboard can help me get the value of the resistor that I indicate in the image, please.

[elgollo51]

In the boardview it appears without data, but in the schematic neither the value nor the correct position appears

[elgollo51]

The card is a computer 6050A3079801-MB-A01 (01) and is identical to the boardview 6050A2945601-MB A01

[SMDFlea]

I'm attaching the board schematics for the
Corvette-6050a3217501-Mb-Ax2.
This is for Elitebook 840 G8 motherboard, not 850, but I think all labels are the same and could help. I don't have other schematics.

Will upload the 2 BIOS and EC bins tomorrow if needed.

Please post the schematic in the schematic requests forum where other members will be able to find it. Post your bios & EC in the bios requests forum if you want someone to have a go at fixing it.

[momolar]

Please post the schematic in the schematic requests forum where other members will be able to find it. Post your bios & EC in the bios requests forum if you want someone to have a go at fixing it.

I will, thank you.

I'm simply not sure if this is a physical issue with the boards or if it's BIOS related which is why I started a new thread.