HP Prodesk 600 G3 SFF is not turning on anymore

[telefon01]

 Hello,
I'm having a problem with my HP Prodesk 600 G3 SFF computer. I tried to connect the internal speaker and HDD, but I forgot to unplug the power supply. After doing so, the computer completely stopped working; the power button didn't respond. Is there anything else I can do? Is the motherboard burned out? The green AUX LED on the motherboard is lightning.

 

[NonSequitur777]

@telefon01,

Welcome to our HP Community forum!

Yes, when connecting internal components on the ProDesk 600 G3, the system must be fully unplugged because the motherboard still carries standby voltage even when the PC is off. Connecting the speaker/HDD header with power still present can cause a short.

Please try the following basics:

1. Unplug AC power, hold the power button 15–20 seconds, remove the CMOS battery for 10 minutes, then reconnect and test.

2. Reseat the power supply's power cables.

3. Attempt a minimal boot (CPU + 1 RAM stick + power button cable only).

If your PC still will not power on but the small green LED on the motherboard remains lit, that means standby power is present, but the board is not starting the power-on sequence. In most cases, this indicates motherboard damage, and replacement is typically required.

Kind Regards,

NonSequitur777

[telefon01]

So it's a hardware problem rather than a BIOS problem?

[NonSequitur777]

@telefon01,

In my anecdotal experience -most likely yes: all available evidence points to a hardware problem rather than a BIOS issue.

Because the internal connectors were handled while the system still had standby power, a short can occur on the front-panel header or nearby traces. When that happens, the board may stop responding to the power-on signal even though the green standby LED still lights.

A BIOS problem would not normally prevent the system from powering on at all.

Since you are getting no fan spin, no beeps, and no reaction from the power button after a full power drain and CMOS reset, the symptoms are consistent with hardware damage on the motherboard.

Unfortunately, at this stage, replacement of the motherboard is generally the required fix.

Kind Regards,

NonSequitur777

[telefon01]

I'm determined to repair this motherboard myself. Do you have any suggestions on what I can measure or check? I've already removed the motherboard.

[NonSequitur777]

@telefon01,

Wanting to repair a defective motherboard is a lofty goal, but that is beyond my skill set -and besides, from my perspective at least, is not worth the hassle.

At least here in the US (please try your local or German eBay site) a replacement HP ProDesk 600 G3 SFF motherboard (p/n: 911988-001) is very inexpensive.

Kind Regards,

NonSequitur777

[telefon01]

In my country, a working used motherboard costs 12€ with free shipping and return policy, so this is probably the best option

[NonSequitur777]

@telefon01,

There you go -that's what I would do!

Warm Regards,

NonSequitur777

[telefon01]

Out of curiosity, I made a full BIOS dump with a programmer and it looks correct, so it's probably a hardware problem that won't be easy to fix.

https://mega.nz/file/p1Zi0Iha#Av184Z6PuTDmjVhjaJV5XJjIx_Rp4i_Pz0N2d-W4I4A

Can you check if this bios is correct?

[NonSequitur777]

@telefon01,

I was unable to read back your dump file on my end in a legible format.

The latest BIOS version for an HP ProDesk 600 G3 SFF is 00.02.51 (August 2024), with previous versions going back to 00.02.02 (January 2017): https://support.hp.com/us-en/drivers/hp-prodesk-600-g3-small-form-factor-pc/15292277.

Kind Regards,

NonSequitur777