hp z820 turns on and turns off

[racerblur]

Is possible if the the fan shroud is not seated correctly it can cause the same problem?

[DGroves]

no, the fan shroud will not prevent a boot, it will however cause bios error msg's about the fan(s) not responding

you have a no boot issue, you might want to remove the cmos battery unplug the power supply for 30min then reinstall

a corupt bios firmware can also cause this, IE- boots black screen blue power light on and fans ramp up to max speed

if you have these symptioms you can try a try bios recovery

https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Crisis-Recovery-Ju...

[racerblur]

Press the power button for split second it lights up and shuts down and nothing. Is that still be cmos? Or maybe the processors need to be reseated? I had the computer shipped and I reseated everything except the processors. Thanks for quick response!

[DGroves]

let's back up a bit,

was the system previously working ? if so when

was it shipped or moved to a new location and now fails to turn on?

did you add new hardware and now it's having power issues?

the power on then right off is usually because of a short somewhere and the power supply is detecting this short and powering off to prevent further damage

as previously mentioned, i would remove all cards, disconnect all drives and remove all ram

then install only the minimum ram needed to boot (this depends on the number of installed cpu's)

make sure the ram is in the correct slots you will be using either 3 or 6 modules

ram locations can be determined using the diagram found on z820's the side cover

then using the z820 service manual verify all the connections to the motherboard are correct

you need to check the main power connector the aux cpu power and the aux ram power connector i have seen people use the wrong connector for the video card and swap the aux cpu power with the aux ram connector look at section " System board designators " z820 section

http://h20628.www2.hp.com/km-ext/kmcsdirect/emr_na-c03424977-1.pdf

[ClaudeWilliams]

Hello,

I had exactly the same problem and fixed it very easily.I sprayed the whole inside of the PSU with electronic contact cleaner.

It worked. The Z800 runs like a charm again.

This is because of  a faulty PSU, Power Supply Unit.

My solution was. Disconnect the PSU from the wall socket.  Take the left panel from the Z800 to open the case. Put on sonme anti static gloves, i never do but before people here start to complain ;),  Take the PSU out (with the black handle on side of the PSU). THen Screw all screws on the top of the PSU loose and take the top plate of. Then give the whole inside of you PSU a

nice bath of electronic contact cleaner. Yuu can buy this online or in any hardware store.

Let it dry for about 10 sec and put the PSU back in. Put the power back in the PSU and..Voilla!!...

I hope this works for you too. If not you need a new PSU.

Claude