Z840 Startup Problems - Single White Flash. No Beeps

[pavel210]

Hi,

I recently got a Z840. It was used and came with just the case, psu, motherboard and 2 Z coolers.

I would like to get some help trying to bring this machine back to life.

I installed a CPU (Xeon E5 2699 V4), a single stick of 32GB LR RAM and a Quadro 600 card.

When I press the power button, I get a momentary white LED and then nothing. No beeps and no red lights. Everything just stops. The case front and back fans spin momentarily. I noticed that the fans on the CPU/RAM cooler attachment do not seem to move.

I followed the diagnostic steps to confirm that PSU is fine (green LED + fans spin).

If I remove the CPU, then it correctly gives me a red light / beep. So I know something is working and it is able to detect the CPU.

When I unplug the CPU/Memory Power on the motherboard and try to power up, the case fans spin up full power for a few seconds and I get the expected 4 red flashes + beeps.

Not sure what else to try at this point.

Any ideas what is wrong? I am currently leaning towards either a faulty PSU (despite it passing the diagnostics) or the CPU/RAM cooler attachment being faulty. Any ideas how I can isolate this or test this further?

Thank you for your help in advance,

Pavel

[DGroves]

do a clean "factory" bios reset  (you must follow "ALL" steps, skipping steps may not do a full cmos reset

remove the power cord, then press the front pwr button till the front light/beeping stops

now remove the side cover and remove the cmos battery for 10 sec, and also press the cmos  reset button for 3 sec

reinstall battery, side cover, pwr cord and try restarting,  i've seen z820/840 systems take up to 20 sec to startup when the cpu(s) have been changed and they will reboot 2/3 times before loading the OS from disk/ssd

also if dual cpu's, i recommend you install ram for both cpu's,......... place one dimm module in  dimm 1 of the lower 4 memory slots on both cpu memory banks if single cpu then only use  right side lowest dimm slot

https://www.itcreations.com/user-manuals/z840/c04400043.pdf

[pavel210]

Thank you for the quick reply.

I followed the CMOS reset steps. Unfortunately no change.

[DGroves]

try a cpu that hp lists in the z840 quickspecs the v3 ones are the cheapest to buy on ebay

early z840 quickspecs

https://www.dectrader.com/docs/set06/492808/15098_ca.html

later quickspecs has v3/v4 cpu

https://www.dectrader.com/pdf/quickspecs/15098_na/15098_na.html

also your current cpu(s) E5-2699v4 REQUIRE the 1125W Power Supply (1450W at 200V Input Voltage) 

[pavel210]

1: How can I tell if my Z840 is an earlier model or a later version?

2: Is Xeon v4 support only possible in the later models? Is this a motherboard limitation?

3: The PSU is labeled "DPS-1125A B-1 A Rev 03". I think that is the more powerful 1125W one.

4: I ordered a Xeon 2630 V3 and will try that once it arrives.

[DGroves]

unlike the earlier z820/z800 systems the z840 only has one board revision that works with v3/v4 xeons

DPS-1125A B-1 A Rev 03 is the upgraded 1125 watt power supply

place the Xeon 2630 V3 cpu in the socket that is closest to the front of the case (cpu-0)

remove all dimms except for the cpu-0  socket that is closest to the bottom of the case (dimm-1)

post a picture of the dimm module label you are using if all labels do not match "EXACTLY" post pic of them also

[pavel210]

1. The 2630 V3 finally arrived. I plucked it in and .... everything came to life! I was able to boot past the BIOS and into a live distro!

2. This means that the issue is with the 2699 v4. I actually have two of them, and they both refuse to power up. Hence I don't think it is a problem with a faulty one I have but something on the motherboard or PSU.

3. Is there anything I need to do on my motherboard or in the case to enable / disable V4 vs V3 CPUs?

4. Could this still be a PSU problem? I am thinking of trying a 2660 V4 next. Its the most powerful V4 chip that does not require the 1125W PSU. If it works, then its likely to be a PSU problem. If it does not work, then it is a V4 support issue.

5. Not sure if its related, but I noticed that the CPU/Memory fans do not seem to be spinning up and the BIOS screen gives me a errors like "517-Memory configuration requires a Memory fan and this fan is not detected" and "511-CPU fan not detected". Any ideas?

My RAM is attached below:

I only have 1 stick for now but plan to slowly buy more as I come across them online. I understand that it should work as long as I use the same LR ECC kind and the same frequency.

[SDH]

What version of BIOS are you using? If your BIOS has not been updated then your newer processor(s) may not work. Perhaps that is why it was sold in the first place. You have to get the workstation to function before you can update its BIOS, obviously. Maybe you are 1/2 done with your project now that you have the workstation running. I'm guessing you have two perfect E5-2699 v4 processors but don't yet have a BIOS version that knows how to run them.

The "microcode" of newer BIOS released by HP can enable function of newer processors. There is a very safe way to update BIOS from within BIOS which is the only way we do it now. Updating from within the OS has significantly greater risks in our experience.

Attached below is a PDF on how we do this.

[DGroves]

depending on how old your current bios is, the latest one may indeed allow your 2699 v4 cpu's if not look at the hp quickspec link i previously posted and select a listed v4 HP approved model note that only RETAIL cpu's  should be used engineering or eval "SPEC" cpu releases are to be avoided

the main black plastic shroud holds all of the cooling fans for the motherboard remove it and look at the underside, you should see all fan locations filled if you see a open location that's most likely the one for the second cpu option and you will need to buy the CORRECT HP fan wrong fan models may not spin at the proper speeds

https://www.amazon.com/BestPartsCom-Cooling-Compatible-Workstation-647113-001/dp/B08BCDWS8P

there are also two front fans that connect to headers located on the front edge of the motherboard in the middle of the black card guide

https://www.serverparts4less.com/530551-001-hp-dual-fan-for-z800-z820-z840-workstation/

last there are two rear PWM case fans that use a custom 6 pin motherboard header

https://www.cpumedics.com/hp-644315-001-90mm-rear-dual-fan-assembly-for-hp-workstation-z620-z820-z84...

pict of the main black fan shroud underside showing the two cpu cooling fan's  (and the two memory blower fans)

https://notebookparts.com/products/genuine-hp-z820-z840-cooling-fans-and-shroud-assembly-684574-001

[pavel210]

I checked that the machine was running BIOS version 2.32.

Followed your instructions to update it via the BIOS menu.  Confirmed the BIOS now shows version 2.61.

Swapped the 2699v4 back into the socket. Cleared the CMOS.

Still the same single white flash and nothing happens. Retried all 2699 chips I got one at a time - same thing.

If I put the 2630v3 back in, then the machine boots.

Any ideas?

I am attaching a photo of the motherboard serial.