Dell R720 - I cannot see CPU 2

Question

Hi everyone, So I got 3 x defective R720s. Two of them won't boot at all, so they probably have dead system boards, but the last one boots and works seemingly fine. However, I just cannot seem to get it to see CPU 2 and it's associated RAM. I tried swapping the CPUs around, reseated them multiple times, clearing NVRAM, running diagnostics etc. It just seems that it won't become aware that there is a CPU in the socket. I went to look at the CPU socket pins, as I assumed there would be something damaged or bent, but to my surprise, they all look fine to me. I figured I would see if the CPU got warm at all, so I measured it, and there is certainly power going through it, as it heats up during boot. How can I figure out what the root cause for this is?

pandaym · Answer

Also I must add, I updated the server to all the latest versions of everything. Did that slowly but surely to avoid problems, by going through recommended sequence. Also I get things like this in my logs: HWC2005 The system board Riser 2 cable or interconnect is not connected, or is improperly connected. HWC2005 The system board Riser 1 cable or interconnect is not connected, or is improperly connected. HWC2005 The system board Riser cable or interconnect is not connected, or is improperly connected. I tried to swap around with different risers from my other two systems, and the risers problems do not always show up. However, it haven't helped discovering the CPU.

Daniel My · Answer

Hello

The riser issues may be related to CPU2 not being functional. The PCI controller is on the CPU, and if both CPUs are not functional it will limit the available slots and or lanes.

If you have tested known good CPUs in the slots then it sounds like a slot issue. It sounds like you bought a bunch of faulty systems that someone was selling for parts. You can try moving hardware around to build a functional system, but if there are system board issues with every system you will need to get a functional system board.

I don't think we validated any CPUs on the R720 that do not support dual CPU configurations, but you should check the CPU model to make sure it supports dual CPU configurations. Also, make sure you are using the same model CPU in both slots. If you are using different model CPUs it should give some kind of CPU mismatch error. You can find manuals on the system support page.

http://www.dell.com/support/

Thanks

pandaym · Answer

True, I did buy 3 servers off a guy that sold them as defective. Two of them as having "dead iDRAC" and the last one as having a problematic CPU 2 socket.

I figured I might be able to somehow fix at least the one with the CPU socket. Is there nothing I can do to look for a fix in the electronics other than replace the system board?

The two other R720's with dead iDRACs seem very dead. Tried every step I could find online but they don't wake up. One of them won't power on at all, it just flashes quickly in the power button when I connect power to it, and nothing else happens. Also the iDRAC has no NIC activity and nothing on display.The other one has no info in display, no activity on iDRAC NIC, but it does in fact power on - but nothing comes up on screen.

Any clues as to whether I can combine some of this?

Daniel My · Answer

I think you should be troubleshooting the power systems. The PSU, power distribution board, and the control panel(Power button). The PDB may be integrated into the system board. If the PSUs connect directly to the system board then the PDB is integrated.

You may have iDRAC issues, but that is not the only problem. If the only issue on the system was that the iDRAC was not functional then the system would come up to an iDRAC initialization or communication error. You would still get video, and the system would partially complete POST. On some systems you can still boot into an operating system without a functional iDRAC. Some systems will not go past the iDRAC initialization failure.

PowerEdge Hardware General

Dell R720 - I cannot see CPU 2

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