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October 25th, 2022 02:00

Unable to power on the host because an SL cable is connected to an unpowered device

Hey everyone,

I have a PowerEdge R750xa which was running fine until recently. After briefly opening the chassis yesterday to simply check for the GPUs, it won't boot up anymore.

All internal devices appear to be connected correctly. When plugging in the power supply, the front panel indicates "Initializing...", then just briefly shows the message "Chassis is open" and finally only shows "Unable to power on the host because an SL cable is connected to an unpowered device".

I interpret this message as some device is connected through data cables but not to any power supply. However, upon multiple inspection I cannot find anything like this...

Can anyone help me out with this and push me in the right direction? 

Best regards,
Manu

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4.4K Posts

October 25th, 2022 06:00

Hello nickel3,

 

We have seen this if the controller card is totally or partially disconnected from the backplane.

 

Shut down, remove power.

Loosen  the blue screws for the front controller,   reseat the controller  and tighten the blue screws.

Reseat SL (slimline) cables, and cables to backplane on both ends.

 

Dell EMC PowerEdge R750xa Installation and Service Manual

https://dell.to/3TS1LhZ

 

1 Rookie

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2 Posts

October 25th, 2022 09:00

Good evening Charles,

thank you very much for your help. I think the controller and respective blue screws are meant to be at the front side of the machine. I saw a depiction of it on the GPU-riser removal instructions. However, that is not installed in my machine at all.

I then carefully lifted the fan array and found two connetors of the left GPU indeed disconnected from the board. Obviously, this is rather embarassing on my side. But I am just happy to have it up running again.

Thank you very much for your input once again. 

Have a good evening, 

Manu

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November 5th, 2024 14:26

We just had this happen with and MX750c blade/sled.  The remotely connected users  were doing updates and rebooted the blade/sled, which was running VMWare esxi 7 and it would come online with power, and same error message.  Literally nobody touches this system, but I checked all the power connections, which were good, so I just detached the blade for a couple of minutes, then reconnected it and powered it on.  Took about 5 minutes or so, but it came back online.  I'm checking that blade's logs to see if anything shows up.

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November 28th, 2024 01:40

@KevinD-HCL​ same problem with MX750c, when im update bios version from 1.11.2 to 1.15.2

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5.1K Posts

November 28th, 2024 06:34

Hello I don't think MX750c should be running this BIOS version.

Image

The highest validated for MX baseline 2.20.00 1.14.1

Image


https://dell.to/3ZcLqsq
You may need to check if BP firmware is up to date, it is not part of the baseline.

 

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2 Posts

November 28th, 2024 14:30

Hi

well, I'm downloading from dell.com/support with servicetag,

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2.8K Posts

November 28th, 2024 15:25

Hi,

Please follow the steps Charles mentioned in the previous post.
Shut down, remove power.

Loosen the blue screws for the front controller, reseat the controller and tighten the blue screws.

Reseat SL (slimline) cables, and cables to backplane on both ends.

 

Dell EMC PowerEdge R750xa Installation and Service Manual

https://dell.to/3TS1LhZ

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