HP z820 system doesn't power on

[vhunjek]

Hello,

from the HP manual, I have done the diagnosis procedure: hold the power button for less than four
seconds; hard drive LED does not illuminate, took PSU out and connected power; fan spins and the BIST LED illuminates, so the result is to replace the system board.

Is there a way to be sure that MB is faulty, could there be a case that PSU is faulty despite the fact that BIST LED illuminates?

The background is that system was powered from unplugged power bank which has UPS feature to test how long it would last in case of power failure.

It went through POST fine, but power bank overload protection cut the power when OS started to load.

After that, there is no sign of life, any help is appreciated.

Kind regards,

[vhunjek · Accepted solution]

I have found a similar issue here and suggested procedure:

only thing i can suggest is to do a "factory" bios reset,.....remove power cord then press pwr button 10 sec and then open case remove cmos batt then press cmos reset button for 3 sec and then reinstall cmos batt and power cord and press power button to see if it powers on, if so enter bios and set time/date

Would that really help? BIOS to prevent power on?