Build #3 - PSU Cables & SSD's, etc...

[rvassar]

I'm stalled waiting on 16Gb of ECC memory to arrive. But I've started cabling up the Supermicro X9SCL in the HAF 912. I've discovered a minor flaw in my plan. The HAF 912 is one of those tower cases that put the PSU at the bottom. The X9SCL mounted in a tower has the 24-pin power header all the way at the top. My PSU's 24-pin harness is too short. I'm looking at extension harnesses as a temp fix, but worry about the reliability & voltage drop. If anyone has any precautionary tales, horror stories, etc... Please speak up!

While searching for local availability, I found Fry's has the little 60Gb Patriot Flare SSD I use as a boot device on sale for $18.99. So it looks like I'm getting a log device. :)

 

[Chris Moore]

My PSU's 24-pin harness is too short. I'm looking at extension harnesses as a temp fix, but worry about the reliability & voltage drop. If anyone has any precautionary tales, horror stories, etc... Please speak up!

I solved that problem once, or twice, using some bulk wire, shrink tubing and a soldering iron... I may be all wrong on this, and I will take my lumps if someone wants to correct me, but the amount of current pulled by that system board should not cause a problem with the wire unless you went much longer than the distance needed inside even that case.

 

[rvassar]

I solved that problem once, or twice, using some bulk wire, shrink tubing and a soldering iron... I may be all wrong on this, and I will take my lumps if someone wants to correct me, but the amount of current pulled by that system board should not cause a problem with the wire unless you went much longer than the distance needed inside even that case.

I actually seriously considered that. Most of the current is going to come off the 12v EPS rail, and get switched down to 1.5v & 1.35v, etc for local use. But the 24 pin connector carries 5 x 3.3v lines, pins 7,8,19-21. I have absolutely no clue how much current a modern motherboard pulls off the PSU 3.3v supply. So I swagged a guess of 10 amps, and added 24 inches of 18 awg, and plugged it all into a voltage drop calculator, and got 0.26v lost, or 7.7%. Inside 10%, but... The PSU's spec claims it can produce 25 amps @ 3.3v! 24 inches of 18 awg produces 0.64 volts lost, or almost 20%, going up to 14 awg gets it back to 0.25 volts.

Given the variables, I figured I'd probably spend as much on the heat shrink tubing & wire as I did on the $7 RaidMax 9.8 inch extender. Flip side, I'll now have extra pin connections, which have their own voltage drops, and reliability problems.

In case anyone wants it:
https://www.calculator.net/voltage-drop-calculator.html

 

[Chris Moore]

Given the variables, I figured I'd probably spend as much on the heat shrink tubing & wire as I did on the $7 RaidMax 9.8 inch extender. Flip side, I'll now have extra pin connections, which have their own voltage drops, and reliability problems.

I looked at the option of building the extensions and buying them, but the thing that made the decision for me was the waiting. I used the thicker wire, but once upon a time, I did that kind of work and had all the wire, solder and heat-shrink tubing already on hand. I was able to do the work myself on the same day I decided I wanted to do it and didn't need to wait for anything to be delivered.

 

[rvassar]

I looked at the option of building the extensions and buying them, but the thing that made the decision for me was the waiting. I used the thicker wire, but once upon a time, I did that kind of work and had all the wire, solder and heat-shrink tubing already on hand. I was able to do the work myself on the same day I decided I wanted to do it and didn't need to wait for anything to be delivered.

That was the kicker... No waiting. I have most of the stuff in a box somewhere, but I don't have the larger wire handy. I want to get back to burning in the other components, and I work 1 mile away from Fry's. (Which presents all kinds of impulse control challenges!)

 

[Chris Moore]

and I work 1 mile away from Fry's. (Which presents all kinds of impulse control challenges!)

LOL.
I guess that it's a good thing we have no shops like that near me.
I would buy too much.



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