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Replacing Supermicro power distributor

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#1

tdlr

Can I replace this power distributor:

25

With this one?

42

Without replacing the power supplies. Power source is 120V.


I have a faulty power distributor in this jbod unit.

https://www.supermicro.com/products/chassis/3U/837/SC837E16-RJBOD1

The unit is EOL and the distributor (PDB-PT837-8824) basically doesn’t exist anywhere in the US. I can only find it on some sketchy looking European sites that I haven’t been able to navigate.

So I am looking for a distributor with the same specs, or close enough that it will work.

This is the one I am currently looking at. It appears to have an identical chassis/form factor, is 23-pair, has 24-pin, molex, etc that I need.

https://store.supermicro.com/pdb-pt826-s8824-power-distributor.html

Here’s a server spec with it: https://www.supermicro.com/products/chassis/2U/826/SC826BAC4-R1K23WB

So it looks like there is some variation in the 200+ volts specs, but the ~120 looks almost identical. I’m assuming that is referring to the incoming power, which will only ever be 120.

I’m a little in over my head on this one, so if anyone with more electrical knowledge can give me an idea of whether or not the tolerances here are air tight or if there’s some wiggle room, that’s all I’m looking for.


#2

If the pinout on the interface is the same don’t see why it would matter. This is the distribution that hooks into the PSU correct so if they mate the same and has all the connections you need shouldn’t be an issue.


#3

Yeah, “Gold Finger Backplane” is just a slot that the PSU slides into with contacts. The form factor appears to be identical, I just don’t want to fry something because I didn’t understand some nuance of in the specs.


#4

Doubt your pulling 1000w so doesn’t matter it’s just that it can generate more if you feed it higher


#5

Yeah that was my thought.


#6

It’s ordered so we’ll see.


#7

It’s short one molex. I miscounted.

(ノಠ益ಠ)ノ彡┻━┻

It also needs a 24pin extender.

I have 2 4-pins and 1 6-pin. Any way to swig that into a molex?


Never mind. Complete failure. The power distributor slot doesn’t line up with the power supply.


#8

https://goo.gl/images/WEFmZh
Need a 5v fr somewhere maybe take it off another molex so just extend it a bit longer


#9

Wait might still have a chance. It might have been bent.


#10

I have a 4-pin peripheral.


#11

Could just repin that cable to molex connecter easy mode


#12

Is there a spec for the amperage? This molex will be responsible for powering 4 drives.

I did find one but only on rbay which is always suspect…


#13

honestly i dont know enough on wire gauge to properly advise or the draw of you drives. I would guess it would be ok, but not 100% on that, drives draw a lot less than gpus and usually those are the adapters that have issues


#14

@MazeFrame

Do you know how much amps can go thru the different wire gauges?


#15

The backplane takes 4 molex for power. I believe each is responsible for 4 drives each (they don’t all dump into one power pool for all drives). Based on seeing a lot of molex to 2x floppy powe, my guess is that molex is a higher power standard despite the voltages being the same.

Also, update here, that pdu did end up working. It was slightly bent before. However, I could not get the front backplane to work. The back on does work though.

I had tested the front backplane in another system and it did work there, so maybe it’s just on the edge of life. Replacement is $250. Might go for it. Already in pretty deep on this one.


#16

Had to look up the gauges, but it is approximatly like this:

 (mm² * 20) - 1 = amps
AWG mm² Amp
17 1.03 19
18 0.82 15
19 0.65 12

#17

Do you know if amperage is included in the molex and/or berg specs? In this case, the concern is delivering enough power to a molex connector via an adapter. The voltages line up but the berg looks like it carries less power.


#18

As Molex has amperage included on nearly all of the connectors on their website, I would imagine they have that also in their data sheets.


#19

Ok yeah, I found it. 11 amps for molex, 3 for berg… so that adapter is probably a no go. Damn. Idk what to do here.

http://www.playtool.com/pages/psuconnectors/connectors.html#floppy

Or actually this site says molex is 5 amps, so now I’m confused.

http://www.playtool.com/pages/psuconnectors/connectors.html#peripheral

Not that it matters, 3/5 still means the adapter is a bad idea.


#20

are you sure each one powers 4 drives and not just a big backplane with multiple sources for input?(Like the dual 8 pins not needed for power on boards that have them) have you tried powering it up as is for a test to see if the drives get power

Drives shouldnt be that much
“The Hdd: +5V 0.72A, +12V 0.52A, Barracuda 1TB, 7200.12”

What drives do you have? I know SAS high rpm drives use more power then that example above.

" How many HDD’s off 1 Molex? PICOPSU

Four drives should be fine.

The maximum current rating for the standard " Molex " drive power connector is 11 amps per pin. So you can get, as far as the connector is concerned, 11A at 5 volts and 11A at 12 volts. These are “returned” through the ground pins, so you don’t get 11 more A through each ground pin! The current you return through the ground pins is the same current you got from the + pins.

The +5 usage of a hard drive will be well under half an amp, so we can ignore that.

Most hard drives pull from 2 to 2.5 amps on the 12 volt line for a few seconds when they spinup, so four drives could get you to 10 amps. If this was a continuous draw I would say this was too much, because that “11 amps per pin” is for a 30 degrees C rise above ambient at the connector. 30C is almost 54F. That’s a lot! If ambient is 70F that means the +12 pins would be heated to 124F. Not good.

That would make me very uncomfortable if it was a continuous draw, but it isn’t – it only lasts as long as spinup takes. What’s the continuous draw? For some reason both Seagate and WD have gone to rating continuous operation in watts, not amps. The typical consumer drives are 8 watts or less, which at 12 volts is less than an amp (again, we’re ignoring the draw on the 5 volt line, as it is negligible). With four drives you’d still be under four amps, less than half the connector’s ampacity.

So four drives should be fine. I wouldn’t try for more, though.

If your motherboard or controller can be set to sequence the startup of your drives, so much the better.

Seagate desktop drive specs: http://www.seagate.com/www-content/product-content/desktop-hdd-fam/en-us/docs/desktop-hdd-ds1770-5-1409us.pdf

WD specs for their “Green” drives: http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-800026.pdf

–Jamie Hanrahan"