Z820 does not boot; no fans revving

[peteGroove1]

Hi,

after I transported of one of my Z820s, it doesn't boot any longer.

The last thing I did on the machine was replacing the thermal paste of the CPUs a few weeks ago.

Problem description:

When I press the power button nothing happens.

I have had errors with these machines before but I always got at least one of the diagnostic codes (sound or blinking LED), now just nothing happens.

What I have done so far:

1. Checked the power cable connections on the board.

2. Checked the PSU: The fans rev up when I connect the PSU to power and the LED is on. This suggests the PSU is fine.

3. Remove all drives and the secondary CPU.

As anybody else an idea what could be the problem?

Best

[DGroves · Accepted solution]

remove power cord, press pwr button 5 sec, open cover remove cmos batt then press cmos reset 5 sec

replace cmos, cover power cord and try power on, if still nothing

remove cpu's ram HD's usb devices and all pci-e cards (including video) you want just the bare motherboard connected to power

now power on, does the system give a beep error (it should) if not board appears to have failed

if beep install cpu -0 and ram for cpu -0 boot again you should get beep/light code for video error if so install video card and boot again, if good install main boot drive only and test again, if you follow this you will see we are testing one subsection at a time so if a no boot happens we know what triggered it

[peteGroove1]

Thank you for your fast response.

The CMOS reset and replacing the battery did the trick. The battery had only a voltage of 2.78 V left.