Z820 - Power button LED blinks 4 times (red) with beep... graphics card (Quadro 4000) bad??

[DriesV]

Hi,

My Z820 in the office is suddenly having some hardware malfunction.

When I power on my machine, the PSU/system fans don't rev up and the Power button LED blinks red with a beep 4 times.

According to this troubleshoot page this indicates a faulty PSU on new UEFI machines:

HP Desktop PCs - Computer Does Not Start and Emits an LED or Beep Code

Section 'Beep and LED code descriptions'

I get the exact LED pattern as the 'Power supply failure' example.

So, I got a new PSU replacement. I still got the exact same LED pattern and beeps...

So, I delved deeper and found that when I removed the Quadro 4000 graphics card and then power on my machine, the Power button LED is solid blue (LED code 'Computer on - S0 (normal operation)') and all fans spin normal.

The Quadro card seems to be the culprit...

Sadly, I have no spare graphics card laying around to verify this, so I'm waiting for a replacement graphics card (through HP service) to arrive tomorrow.

Is it possible that the Power button LED code (4 times red with beep...) has nothing to do with a bad PSU and that my Quadro is bad?

Dries

[SDH · Accepted solution]

Dries..... that Z820 has been giving you some headaches.

Many of the error codes have not changed from the earlier workstatons.  I have hit this error beep series in the past and it often does not mean that the power supply itself is the exact cause.  It may be a hardware device down the chain that is causing an overvoltage at the power supply, triggering its "crowbar circuit" fault protection:

http://en.wikipedia.org/wiki/Crowbar_(circuit)

Here are the instructions for dealing with this set of beeps from an earlier HP xw technical and service manual.  Note number 2 in the troubleshooting instructions.... you don't usually have to get down to number 3, in my experience.  I think you have already found the faulty device:

Power supply failure.
1. Open the access panel, and be sure the power supply cable is properly
connected to the system board.
2. Locate faulty device by removing all devices and then reinstalling one at a time
until workstation fails. Replace the device causing the failure. Continue adding
devices to ensure all are functioning properly.
3. Verify the power supply functionality.
a. Disconnect AC power.
b. Remove all internal power supply cables from the system board.
c. Plug in AC power.
● If the power supply fan spins and the BIST LED illuminates, then the
power supply is good. Replace the system board.
● If the power supply fan does not spin or the BIST LED does not
illuminate, replace the power supply.

[DriesV]

UPDATE:

Today a brand new replacement Quadro 4000 arrived.
This replacement did indeed fix my system! I'm a happy man once again...

Dries

[DriesV]

Btw,

I think the cooling on my old Quadro 4000 had been bad since day 1. In CPUID Hardware Monitor the idle temperature was always 78°C. I thought this was normal.

Now on my new card the idle temperature is a steady 57°C. That's a whopping 30 degree difference!

That or the temperature sensor was bad...

Dries