SuperMicro H12DSi-N6 with Dual EPYC 7B13s won't boot after putting inside case

High-Performance Computing Workstations & Servers
1

I had been running this system for more than 6 months in an open environment and decided to finally put it inside a closed case, so I changed my main PC’s case to use the Corsair 7000D Airflow.

The system was previously running with 4 140mm fans, 1 120mm fan directly pointed to the VRMs with a 3D printed fan duct and the CPU coolers (Arctic 4U SP3s).

To this configuration I added 3 more 140mm fans and 4 120mm fans (out of which 2 are not PWM and I already tried unplugging them to solve potential incompatibility issues without luck).

To run the additional fans I am using the case’s built in fan header which is directly connected to FAN2 header on the motherboard and a sata cable for power.

All fans are connected between FAN1 and FAN6 headers and FANA and FANB are not currently plugged in.

I have also switched my PSU from an NZXT C1000 (80+ Gold) to a Be Quiet! Straight Power Platinum 1200 (80+ Platinum) because the NZXT’s 24 pin cable would not reach the PSU because of the massive size of the motherboard.
NOTE: I am using CPU cables from a Quiet! Straight Power Gold 1000 (80+ Gold) because I am not able to find the Platinum’s box with cables unfortunately. I already wrote to the BeQuiet! support to confirm the compatibility of the cables even tho they are from the same product line.

I am able to log into the IPMI dashboard and some LEDs are on on the board, but I am usure if the motherboard is actually getting power or not.

When I try to send the Power On signal from the dashboard, nothing happens, even tho the fans all start spinning as soon as I turn on the power supply. Auto boot up was enabled before.

I am honestly worried about the hardware.
I am not a server expert so any kind of help would be greatly appreciated.

Troubleshooting steps I already took:

  • Taking out the CMOS battery waiting a minute or two and rebooting;
  • Trying to reset the BIOS from the IPMI;
  • Resetting BMC;
  • Updating BIOS from version 2.6 to 2.9 (the IPMI dashboard still displays 2.6 even after completing the process);
  • Plugged out the two NON PWM 120 fans;
2

Best have a systematic approach solving this;

  1. Remove the board from the case and reattach the old PSU you’ve used before. Does the board boot properly? While the board is out of the case, ensure there are stand-offs mounted everywhere they’re needed and none where they don’t. You won’t be the first to make that mistake :stuck_out_tongue:
  2. Mount the board in the case, but keep the old PSU connected (just place it next to the case so the wires reach their destinations). Does it still boot?
  3. Replace the old PSU for the new one with the original cabling that came with that new unit, which is still not mounted in the case.
  4. thoroughly check the extended cables for pin-to-pin compatibility. This may be the reason you fried the board, although internal PSU protections should have done their job (and maybe they do and that’s the reason you can’t boot in the first place) Only if you are 1000% sure the cables are pin-compatible, change the standard ones for the longer ones. See if the board still boots. The new PSU is still outside the case.
  5. only if you successfully complete the previous steps, mount the new PSU in the case and cable-manage the lot. Make sure that no connection is under tension, an inch of slack goes a long way preventing unwanted errors later on.

HTH!

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