HP ProDesk 600 G3 single beep within one second of power on and no POST...

[Deejinoz]

Hi, I was getting the TPM 80090016 KEYSET DOES NOT EXIST so tried to reset the TPM in the TPM.msc (BitLocker is not active on this system). Now when I start the computer up I get a single beep, not LEDs flash but the power LED stays on and the computer does nothing else. No POST, no further beeps or LED flashes and no Windows boot. I have tried unplugging everything and pressing the power button for 15 seconds. Plugged everything back in and powered on with the same result.

According to the HP service manual single beep codes are no longer used. However, this is definitely a single beep and no corresponding LED flashes.

The PSU is clearly OK. The system was working just fine right up until Widows told me I'd need to reboot after clearing the TPM.

Any suggestions?

Could it be a flat CMOS battery or ROM corruption? Shouldn't HP SureStart help if it's a corrupt ROM?

Please help!

[itsmyname]

@Deejinoz -- try this:

1. hold-down the computer's "power" button for 30 seconds, or until the computer powers off.
2. disconnect the AC power-cord.
3. hold-down the power button for a few seconds, to "drain" any residual power.
4. reconnect the power-cord.
5. power-on.
6. if you still have the issue, repeat #1 & #2, above.
7. remove one side-panel, to expose the motherboard.
8. find the CMOS battery (about the size of one $0.;25 coin).
9. gently remove it. There may be a small "finger" holding it down. 
10. repeat #3 &#4 & #5, above.
11. you may get a "CMOS error' message. Don't worry.
12. power-off your computer, remove the power-cord, re-insert the CMOS battery.
13. replace the side-panel, and connect the AC power.
14. power-on, and enter BIOS SETUP, -- hopefully, you can do this, and can reset the date/time.
15. exit from BIOS SETUP.

Tell us how far you get, in the above steps.

P.S. On some of my computers, a "single beep" indicates that "all is well".

[Deejinoz]

Hi @Itsmyname,

Thanks for your response. I got to power on in step 14 with no change. Machine still powers up, single beep and then nothing. As I said, the HP service manual for this model says there are no single beep codes and yet here we are now with a new CMOS battery and still a single beep.

Cheers,

David