How best to handles this Supermicro chassis stupidness?

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Fritz

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Apr 6, 2015
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Chassis is a SM 512. MB is a X9SCI-LN4F.

The MB power cable bundles coming out of the PSU poke up beyond the top of the chassis. In order to get the top on I have to put considerable pressure on it to push the bundles down. Problem is, the system won't boot with the lid on. I think it's because the bundle is pushing against the memory when the lid is on. The bundles, main and 8 pin are too stiff to wedge in between the PSU and MB plus the space is just not big enough. The chassis is correct for the MB so either I'm missing something here or this is a piss poor design. Either way I need to get it working with the lid on.

Any suggestions much appreciated.
 

K D

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Dec 24, 2016
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Can you post some pictures of the setup.


Sent from my iPhone using Tapatalk
 

vl1969

Active Member
Feb 5, 2014
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if the PSU is original for the chassis than you are doing something wrong.
I have seen thing like this, where a wire was not managed properly and was on the way.
it was not an issue with chassis, but me being brain dead :).
took me 3 hours to find a pic on the net to see what I had been doing wrong.
 

BLinux

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Jul 7, 2016
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If you're actually going to customize the cables, let me know and I'll get you the part numbers for name-brand pins and connector bodies. If you're in the US, I can also lend you the crimping tool for the cost of shipping.
I plan to customize the PDB cables for another Supermicro chassis. Would you mind sharing your sources for pins/connectors?
 

Terry Kennedy

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Jun 25, 2015
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I plan to customize the PDB cables for another Supermicro chassis. Would you mind sharing your sources for pins/connectors?
Code:
EPS12V:
  Shell: Molex 0050361713 (black) or 0039012080 (natural) [Digi-key WM11176-ND / WM3703-ND]
  Pin: Molex 0039000039 [Digi-key WM2501-ND]
  Pin extractor: Molex 0011030044 [Digi-key WM9918-ND]
  Crimp tool: Molex 0640160200 [Digi-key WM17551-ND]

PCI Express 6-pin:
  Shell: Molex 0050361672 (black) or 0039012065 (natural) [Digi-key WM4265-ND / WM23702-ND]
  Pins / tooling as above

PCI Express 6 + 2-pin:
  Connector as above, plus Molex 0050361673 (black) or 0039012020 (natural) [Digi-key WM7263-ND / WM3700-ND]
  Pins / tooling as above

Motherboard 24-pin:
  Shell: Molex 0039012245 (natural) [Digi-key WM23711-ND]
  Pins / tooling as above

Motherboard 9-pin USB:
  Shell: Molex 0022552101 (black) [Digi-key WM2522-ND]
  Pin: Molex 0016020096 [Digi-key WM2562-ND]
  Pin extractor: Molex 0011030036 [Digi-key WM1032-ND]
  Polarizing key: Molex 0015040292 (black) [Digi-key WM1033-ND]
Of course, if you're going to make / modify your own power cables, you will want to use a power supply tester to make sure you don't blow anything up. The squashed-hexagon one is pretty ubiquitous (not my pic):

Click the pic for a link.
 
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Fritz

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That's a pretty bizarre location for the MB power connectors.

How about cutting the 2 cable ties and working the wires down to the correct location one at a time?
Thanks, I'll give that a try. The wires were bent in that direction when I opened the chassis for the first so I suspect the original MB had the connectors in the same place.

This is going to be a PfSense box, this is why I went with a 1U case. I want it to be small and flat. It will sit loose on top of the rack.
 

Fritz

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Cutting the cable ties and pushing the individual wires into the crack did the trick. Problem was, with the bundles cable tied, the excess wire directly above the connectors was rigid and formed a "bump". It was this bump that made the lid hard to get on. If I wasn't so d*mned frustrated I would have seen this yesterday. Thanks Terry for pointing this out.
 

Terry Kennedy

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Cutting the cable ties and pushing the individual wires into the crack did the trick. Problem was, with the bundles cable tied, the excess wire directly above the connectors was rigid and formed a "bump". It was this bump that made the lid hard to get on. If I wasn't so d*mned frustrated I would have seen this yesterday. Thanks Terry for pointing this out.
Now that they're where you want them, you can probably re-tie them to neaten things up and keep stray wires from escaping. That will tend to pull the bundle into a circular shape, so it may not work if the space is too narrow. But you should be able to tie smaller numbers of wires together - you can create arbitrary shapes of "bundles of bundles" and then put a tie around the whole thing.

OTOH, if it is working and the lid is on, may as well leave it as it is...
 
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Fritz

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The new baby made it through the night, so everything must be OK. :)
 

K D

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Had similar issues with a 505 chassis. Cut the zip tie, bunched up the wires again holding them tight so that they stay low and re zip-tied them.

Ended up replacing the heatsink with an active cooler and getting rid of the shroud. They need to re think the design.

6B730200-97D3-46AB-97C9-36305DBA509B.jpeg
 
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Terry Kennedy

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Had similar issues with a 505 chassis. Cut the zip tie, bunched up the wires again holding them tight so that they stay low and re zip-tied them.
That's really the only way to go if you ever plan on re-using the power supply for a different motherboard. I chop the PDB cables because I got a bunch of PDBs for cheap (something like $35 for 8 of 'em) so I don't mind tossing the modified PDB and putting another one on if I change motherboards. I also swapped out the HA (High Availability, space for a 3rd PSU or BBU) PDB in a chassis I got used for the regular one, so I didn't have to chop up my only HA PDB.

One important note - you can get pretty cut up if you drag your hands across the cut ends of cable ties like you show in your picture. In the 90's there was a big workplace injury settlement because a telco tech apparently ended up slitting his wrist on one of these, so they banned them and went back to lacing cord (for example).

There is a special tool that both tightens and cuts the end of the cable tie, the idea being that the cut end pulls back into the head. But the inexpensive ones are poorly made and only work on certain brands / sizes of ties and can be impossible to get into position on an installed tie. I recommend black cable ties with metal retaining clips in the head instead of the ridges all down the tail of the tie. The white / clear ties do not have UV resistance (not needed inside a chassis) or strengthening agents (useful), while black ones should. I recommend T&B ties such as the TY525MX, and cutting them with sharp flush nippers like Xcelite 170M right up against the head.
Ended up replacing the heatsink with an active cooler and getting rid of the shroud. They need to re think the design.
The shrouds can be very useful. On my SC836 I have active CPU coolers and still use the shroud.

I suspect that if you purchase a complete chassis + motherboard (AKA Superserver) from Supermicro, you get a better cable arrangement. They may use made-to-length cables, or include additional cable management not provided with the chassis alone.
 
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K D

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I have been swapping a bunch of hardware around and hadn't settled on what I needed. So haven't done any cable customization in my boxes yet.

I have the tool that you mention that tightens and cuts at the same time but I prefer to use a flush cutter to make it absolutely smooth and twist it so that the lock part is not on the top. I've found that for me it's safer.

If you have a part number for the one that you use it would be great.

On a different note, is there a good molex crimper for 4 pin power cables, preferably a ratcheting one? I have been using a basic crimper that I bought at a local frys years ago and need to replace it.

Here's a picture of the system I am currently working on. Cut and sized all cables. Not to happy with the sas cables but they don't block airflow from the drive vents. I will be using the air shroud with this one as I need to direct air to the AiCs. I still need to add a couple of Supermicro NVMe adapters and the cables before cleaning and closing it up for good.

Feedback welcome.

19A1E850-3A8E-4D54-842F-FA9BC1038797.jpeg DA75A52A-2F51-40F4-AAD0-7FF0670FEFCF.jpeg 89F670BB-36B6-4A5E-A2FE-CB8A14294A90.jpeg
 

K D

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I suspect that if you purchase a complete chassis + motherboard (AKA Superserver) from Supermicro, you get a better cable arrangement. They may use made-to-length cables, or include additional cable management not provided with the chassis alone.
The cables are made to match their system components. If you look at the chassis pages and go to the section where they mention the. Full systems that use the chassis, you will be able to get to a "reference" server. From there you can get to the parts they use. The closer you are to the "reference" box, the cleaner the cable layout.
 

Terry Kennedy

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I have been swapping a bunch of hardware around and hadn't settled on what I needed. So haven't done any cable customization in my boxes yet.
Makes sense. There are only two sizes of stock cables - a little too short, or way too long.
I have the tool that you mention that tightens and cuts at the same time but I prefer to use a flush cutter to make it absolutely smooth and twist it so that the lock part is not on the top. I've found that for me it's safer.

If you have a part number for the one that you use it would be great.
I use the Xcelite 170M nippers, not the cable tie tool.
On a different note, is there a good molex crimper for 4 pin power cables, preferably a ratcheting one? I have been using a basic crimper that I bought at a local frys years ago and need to replace it.
The crimper needs to match the pins, and the pins need to match the housing. Assuming you want to go "real Molex", you want:

Female pin - 0002081201
Female housing - 0015244048
Extraction tool - 0011030037
Crimper - 0638117000 (be prepared for some serious sticker shock)

Frankly, if you're going to be daisy-chaining wires, any hand crimp tool is going to be a PITA. I'd probably just fold over the crimp area with needlenose plier to capture the wires and then solder the wires to the pin to ensure a good connection.
 
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