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11-15-2021 10:11 AM
Hello all,
i have some troubles with my z820. Since last saturday the workstation is not powering up.
first i thougt the power supply is the problem. but when i remove the power supply and connect the power cord i can see the green ligt and the fans are running.
when i put it back and connect the power cord nothing happens..... no light, no running fans, nothing. i am afraid that the motherboard is the problem.. my last hope, it is not.... do you have any ideas how the issue can be solved?
thanks in advance
ThinkAbout
11-15-2021 01:40 PM
@ThinkAbout84 -- when i remove the power supply and connect the power cord i can see the green light and the fans are running.
The green light only shows that the power-supply is connected to AC power. Nothing more.
A power-supply needs to output various voltages, e.g., 5 volts for the disk-drive, and (maybe) a different voltage for the fans. So, a "partially-failed" power-supply may be the problem.
When you power-on the computer, it first runs the POST (Power On Self Test) to check the hardware.
This usually includes briefly spinning the fans at 100% speed (and 100% noise), to confirm that they work. Is that what you are hearing? The POST should throttle-down the fans to a much slower/quieter status.
Do you have access to a different, but compatible, power-supply?
Will your computer start-up normally with this alternate power-supply?
If not, then you probably are correct -- the motherboard has failed.
Did you purchase the computer within the last 7 days? If so, take it back to the store that sold it, and exchange it.
Did you purchase the computer within the last 12 months? If so, exercise the HP Warranty to get HP to repair/replace it, at their expense.
11-15-2021 10:01 PM
good morning, thanks for your reply.
the problem is, that when the power supply is mounted in the workstation i have no chance to start it up. before this issue started, i can remember that every time when the power cord was removed and reconnected again, the fans and the fans spin at 100% for about 2 seconds. but this is not happening anymore. also the power button is "dead".
thanks for the hint with the "partially-failed". i also had the same thought, so i will order a new ac power and test it. unfortunately I bought the workstation from a friend 8 months ago... so the problem is now "my problem" 😉 i will let you know the results.
thanks.
regards
ThinkAbout
11-16-2021 05:19 AM
removing the power supply and then connecting power does indeed cause it to run it Built In Test (BIST) as documented in the HP service manual, "itsmyname" is incorrect in their statement it only shows power
while the BIST test checks most common things it's not foolproof, however in this case based on your post it appears that there is a direct short somewhere that is preventing powerup
try removing all pcie cards except for video, disconnect all internal drives and usb devices except for mouse/kbd (if not PS2)
remove all ram except for one stick (if single cpu) or two if dual cpu's check side panel to see which one(s) to leave
remove power cord, press power button for 10 sec then open side panel remove cmos batt and press yellow cmos reset button for 5 sec
now reseat cmos batt, apply power and see if it will start if not power off and remove video card all ram and both cpu's try power again system should power on a beep error codes related to cpu/ram
if still no power on then system board is most likely bad
note that it's usually a better deal/cheaper to buy a used working z820 and transplant your parts from the defective systems into the new one (drives.ram,vid card,cpu(s) and so on)
also note that only the v2 mothsrboards can run the 55/56xx series cpu's v1 boards are limited to just the 55xx line
here's a board for 98.00 working (ask seller for board label numbers to see what ver it is)
11-17-2021 11:32 AM
@DGroves -- is incorrect in their statement it only shows power
Which lamp? What indication does it show?
Some power-supplies have a lamp adjacent to the socket for the power-cord.
That lamp shows "green" when there is AC power being received.
Some motherboards have a lamp that also lights-up when the power-supply delivers power to the motherboard.
Anyway, as previously recommended, either test with a compatible power-supply, or use a "multimeter" to check the leads of the power-cable that usually connects to the motherboard, or, permanently replace the power-supply, with the hope that the current power-supply is the cause of the problem.
11-17-2021 12:08 PM - edited 11-17-2021 12:10 PM
again, if you want to know more about the z820's builtin power supply test "BIST" READ THE SERVICE MANUAL
the z820 does not use a ATX type supply, the power supply is unique to the z8xx series of computers a user is unlikely to have a spare, and these units can cost quite a bit more than a ATX supply
https://www.compeve.com/Documents/HP%20Z820/HP_Z820_user_guide_compeve.pdf
also covers the z820
https://www.manualslib.com/manual/626336/Hp-Z220-Sff.html?page=145
11-22-2021 09:39 AM
hello everyone.
in the meantime i did severals tests. i ordered an other power suppy .. i am now 100% sure, the power supply itself is not the problem.
therefor i removed everything from the mainboard, removed the cmos battery plugged in the power cord nothing happend. reconnect everything then one linge sign... the fans of the chassis moved for one second.
my next thougt is, maybe the cables itself are the problem? the power button itself doesn't shine. is this an indicator that the mainboard is damaged? what I also didn't find was a status light on the mainboard to show if the board is on power or not. how can I identify it? i think the next step will be removing everything from the tower so see if some cables are broken, right?