Power Supply HP DPS1200FB Server Power Supply

[teisysadmin]

Couldn't find any threads about this PSU when I searched, so I figured I'd start one. This thread isn't so much about the DPS1200 specifically, but any of the HP common slot power supplies.

For those doing 12V builds, these HP server power supplies have a lot of potential as external power bricks. They're cheap (anywhere from $10 to $60 if you know where to look), not much larger than a typical laptop power brick, and they have a history of use by the RC community for similar purposes, so there are some resources out there about the PSUs.

These two videos address the fan speed control modification, which reduces the speed of the fans when the unit is not under load.
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And this blog post goes over some of the specifics of the HP common slot interface:
http://colintd.blogspot.com/2016/10/hacking-hp-common-slot-power-supplies.html

My PSU just showed up earlier today, so I'm currently in the process of modifying it to be used as an external 12V power brick. So far, I've peeled off all of the stickers, ripped off the handles and latches, pulled out the stock fan, and starting messing with the common slot interface.

Personally, I don't really care for the common slot interface, and I'd prefer not to use one of the standard breakout boards that you can buy. Looking at the connector, it appears that it is attached to the main PCB of the PSU with a few solder connections. There are 14 small pins on the left side of the little common slot board, and there are 4 large pins in the middle of the board. I had some success unsoldering some of the smaller pins, but I held my soldering iron on one of the larger pins / posts for a pretty long period of time and it didn't melt at all. If anyone has experience removing the common slot interface from these power supplies, I would very much appreciate the input.

I'll continue to update this thread with photos and instructions / links as I continue to work on this project.

 

[teisysadmin]

So I had some time to work on this project over the past week while I had some spare time at work. I found that the lugs that connect the common slot interface to the rest of the power supply are, in fact, soldered on. There's a lot of mass on those things, so my 40W soldering iron wasn't cutting it. I picked up a 140W gun and made a lot more progress desoldering the lugs in question.

Unfortunately, it still takes forever to melt the solder on those lugs. Last I had a chance to work on this, I threw it under the drill press and tried to drill out the lugs to either remove them completely, or at the very least remove some mass so that the remaining solder on them would melt a little more readily. In more unfortunate news, I wasn't careful enough while I was hitting one of the lugs and I damaged two small traces on the actual PSU PCB. They appear to be signal traces of some sort and they are both very, very thin. The odds that those traces carried signals that are specific to the PSUs function in a server are relatively high so I'm not sweating it too much. If I find that the device doesn't operate as expected once I manage to get the damn common slot interface off, my plan is to use a very small flathead screwdriver to scrape off the solder stop mask above the traces, and then solder some small jumper wires onto these crude pads.

Aside from continuing to struggle to remove the common slot interface from the PSU, I took some time to fill in holes that were previously used for latches, threads for the handle, and some little cutouts for the brass clips designed to apparently ground the PSU to its cage with some JB weld. I sanded down both parts of the enclosure, hit them with a couple coats of primer and a couple coats of matte black paint + primer. It's looking a lot better, but that won't do me any good until this thing is functional.