SuperMicro 936 PSU and PDB upgrade

[serveitup]

Some history, and since it is my first post it seems relevant.



I have had systems in my house, no less than 6 typically, and a few of them hold many drives internally, but the wiring and maintenance is a drag and even the case that are designed for this only work well until they are about half full.



It had been a while since I had upgrade my desktop, I was still running an i7-920, it has 18 gigs of ram, but it is a power hungry beast. I thought to myself if I can get a two socket server running Sandy-Bridge E or newer for the cost of a decent 1 socket desktop why not!



I have read these forums for a few years now about SuperMicro servers in the 3 and 4U class, and I have wanted one. With virtualization I have no reason not to use one as a desktop and server and save some total power demand on the house. (I don’t have any serious client demands in my house at this time and I always reserve the right to repurpose hardware in the future.) I decided that I needed a video card that could run my three monitors and didn’t require and external power header. The Nvidia 1050ti was ready made for the job.



I opted for the 936 from mrrackables and negotiated to get 8x8GB sticks of 1600MHz ram installed for a small upcharge. It has two E5-2650’s which might be a touch slow, but I decided I would watch for deal on v2’s an upgrade to a hotter V2 in a while. The 2650’s only go on ebay for about $50.



I stuck a normal SATA SSD inside the case and ran an adapter from near the backplane to power it, installed an OS and was up and running. The drive bays were empty, but I wanted to get my system running and tested, and I just spent a pile of money.



I then ran across a 43U bare bones rack on CL for $100. It was the type that bolts together making it easy to move. I packed up my electric impact and picked it up. Now I have a rackmount server, in a rack along with everything else. I am pretty happy. The rack is in the basement so noise isn’t a huge issue. My house has centralized computers, I have run HDMI and USB cables out to every desk so that the users (family members) are far removed from the heat and noise. This saves me actual money during the summer, as the AC runs less. Also since the server rack is near the furnace and water heater there is no shortage of noise in the area.



Then I check the power draw, this server OFF draws 50 watts. On it draws 200 something at idle. This is not a good thing. I was hoping to stay power neutral going from an old i7 to the dual E5, and I am not doing it. Temp solution, I plug the server in to the remote power switch and turn off it’s ports when I am not using it. Long term solution, RESEARCH!



Supermicro noise levels

in this thread there is a list of PSU’s, I saw my current PSU and the PSU I wanted on that same list. Physical dimensions were the same, so I bought a pair on ebay for 185 delivered. If they had slid right in, you probably would have never heard from me. They slid most of the way in.



The problem the new PSU PWS-1K28P-SQ has a wider connector than the PWS-1K21P-1R and wouldn’t slide into what I now know as the PDB (Power distribution board). After much searching around I haven’t found anyone changing the PDB out to gain access to newer power supplies even though there seems to be plenty of people doing far more intrusive things in the quest of lower noise. MORE RESEARCH!!!

My chassis

Supermicro | Products | Chassis | 3U | SC936A-R1200B

My mainboard

Supermicro | Products | Motherboards | Xeon® Boards | X9DR3-LN4F+





After much thought and searching of the internet I realized that the safest bet would be to look at chassis’ that were listed on my mainboard page, that supported the Platinum SQ PSU I now own but don’t fit.

The mainboard page lists supported chassis:



2U Chassis

• CSE-825TQ-R740LPB
  
  
• CSE-826E16-R920LP

3U Chassis

• CSE-835TQ-R920B
  
  
• CSE-836BA-R920B

Tower / 4U Rackmount

• CSE-745TQ-R920B
  
  
• CSE-846BE16-R920B
  
  
• CSE-847E16-R1K28LPB

My chassis has PDB PDB-PT825-8824 and I know that doesn’t work so that takes care of a few.



SC836BA-R920B | 3U | Chassis | Products | Super Micro Computer, Inc.

This 3U chassis has the right PSU support as it uses a PWS-920P-SQ, and I decided that it and the 1280 version were almost certainly the same. It contains the SuperMicro Power Distribution Board PDB-PT826-8824 so I dug on ebay and sure enough SuperMicro Power Distribution Board PDB-PT826-8824 - FREE US SHIPPING | eBay for 24 dollars delivered. I looked up my current unit the PDB-PT825-8824 and could clearly see the metal was slightly different but I figured I could easily swap the metal parts between the two board stack.



I plunked down my 24 dollars to go with my previous 185 dollars and hoped the mods would go well.



Yesterday the part arrived, and today I took a look at the situation.



Next post will contain what I did.

 

[serveitup]

I will try to post photos of the job

First step was removing the existing PDB, three screws on top and it slid up and out. It was pretty tightly fit in there.

Without a measurement tool, the four screw holes look like they will fit just fine to cross the electronics over to the other metal.

The different is the top, the new unit only one screw hole on top, not three. It has two parts that hang down over the side for additional screws.

The other thing I realize is that the new unit has screws through the back plate and the old had threaded inserts. I could drill and make this work, but I didn't want to break the working one disassembling it; if I could stick to just modifying the new part. I bought it and had no intentions of returning it even if it didn't work, so modification time.

The metal bits that hang down won't go in to the case, as it has tabs sticking out to receive the screws. I broke the two metal parts off of the new unit that prevent it from going in to the case. Not elegant, but leaves me with a fully assembled and functional original unit, which is a nice plus in case things go wrong.

As I was sliding it into the case, the upper PSU connector hit those tabs that accepted the screws on the old PDB. Guess that explains why they changed the design!

I considered removing those two tabs by breaking them off too, but I was able to bend them up enough to get by, and then bend them back down once the new PDB was installed. The tabs provide additional stability, and I could drill out the new unit to make that work. The holes would be close to the edge, and I am not shipping this thing, so I went with the single back screw that lines up perfectly.

This all hasn't taken very long. The hard part was getting the cables to cooperate, which took some wrangling. They aren't ideally placed, but that is my fault, they could be with more effort. All wires reached the required plugs and after installing the new PSU it fired right up.

Power usage on is down 60 watts from before (200 to 140) and I figured this mod would pay for itself in electricity usage in four years. I didn't check with it off, too curious if it would turn on.

And since no doubt someone will ask, yes it is quieter, like I can't hear it anymore. Before I couldn't hear the system fan's over the PSU's, now I can't hear it as the other stuff in the rack is louder. The switch is pretty darn loud. When it is booting up and the fans are spinning faster, I can hear it, but once it hits idle, it drops in to the background. With the old PSU's I couldn't tell that the systems fans were changing speed. The PSU's that came with it were not the units that were shipped new, they were Ablecom 900 watt Gold units. From over 8 feet away you could feel the breeze coming off of them.

I have many pictures, the site gave me an error when I tried to upload. I will attempt to answer questions.

 

[serveitup]

Looking at it, if I had wanted to make the case permanently converted to the new PDB, I could have broke out the tabs, and put new holes in the case itself to use the downward hanging screw receiving holes on the PDB. Of course that would involve removing the mainboard for safe keeping. In case anyone is attempting this mod in the future, you might consider that course, if you are fine with it being a more permanent modification. At this point my case hasn't been modified at all, just the PDB I installed.

 

[BLinux]

i don't know what your power requirements are, but perhaps it would be easier to go with a PWS-7401P-1R? I recently discovered (too late, after I already purchased some PWS-920P-SQ) these are pretty darn good for $30-$40 (why not the Supermicro PWS-741P-1R?)

 

[serveitup]

I was also a bit short on research before buying the new PSU's. I dialed in on the SQ series and was focused on nabbing them. I paid 92.50 per PSU, so more than double the 700 price. Although I am looking at the long term, this system will get more hungry CPU's, more ram, a RAID controller, and a bunch of big spinning platter drives installed to it over it's life at my house. 200 watts is just the beginning of the power requirements. Will I exceed 700, I don't know. At one point I did some very questionable math that led me to believe I might exceed 900 and since the 920Q were more expensive of ebay I went for the big ones.

Looking at the best picture I can find on the internet it looks like the 700P unit uses the same connector as the 1280P-sq so I would have probably faced the same problem. If there is a really quiet/efficient option that fits the older connector, that would be a good bit of knowledge to make note of for everyone. Failing that, my message is "replacing the PDB unit may not be that hard, or expensive".

I am still enjoying the SQ PSU's, they cost money but they are quiet and efficient. My server now has four spinning disks in it, and my power draw is still under what it had with the old PSU's, even while using the GPU to play video games.

 

[beren]

I'm thinking of doing this for my server, my question is what do you do for gpu power? My backplane takes 4 of the 6 molex connectors, my motherboard has 2 8pin 12v power cables. I'm left with a 4 pin 12v and 2x molex. Right now I am putting a 1060 in, but what if I wanted a 1080ti or better? Do I need to velcro an external PS to it like a modded hp or sm with gpu breakout?