![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1091100;image)
The title pretty much covers it; I got a smokin' deal on a half-dozen of these PSUs made for Dell 1850 servers, so I decided to go in ba**s-deep and designed some 3DP endcaps to make them into a proper (if somewhat loud) bench supply. Maybe more a "chuck it under the bench to get away from the noise" power supply... I dunno.
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
I've used these and various other server PSUs (did dozens of DPS-1200FBs back in the day before the crypto-weenies discovered them and drove the price sky-high) as high-current DC power sources for a variety of purposes; they're great for powering LiPo chargers, charging batteries and powering old-school lighting, as well as lots of other 12V-powered devices like car audio and mobile radio comms. If you know what you're doing, you can "float" the DC side GND with some measure of safety and stack multiples in series as bulk power for those CV/CC voltage regulator modules and bigger LiPo chargers.
That is a "I understand the risks, etc..." mod that we won't be discussing here. Full stop.This project is only about the
relatively safe practice of tricking these things into thinking they're still shoved up a Dell 1850's arse so they'll turn on and tricking them a little more to put out a couple extra volts above stock. The 3DP endcaps I designed here are both around Rev5, so pretty well refined; they do quiet the beast a lot, but you can only do so much with a brick that has a little jet engine inside.
So without further ado, lets get started on the actual build...![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092900;image)
First, I have to make a screw hole in the nosepiece to hold it on. I toyed with the idea of just making it a friction-fit, but I decided a screw was more finished-looking. This terror object is a little jig I made of a scrap of hardened wire screwed to Unit number 1; it will locate the screw hole exactly over and over on multiple parts. Yeah, I could have redesigned the part; I decided on the screw after I had 4 of these printed up. Might as well finish them all "the hard way" as waste valuable production time on multiple iterations to get the hole located exactly right.
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif)
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092904;image)
I apply a little heat from my soldering iron and the hole is made.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092908;image)
A little more heat on one of the screws I plan to use makes a recessed hole that reinforces itself (these walls are 40% infill) in the process.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092912;image)
Stepped screw and matching hole.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092916;image)
Now to take it apart...
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092920;image)
...and the first thing needs to be done is to unplug this cable from the rear-mounted status LEDs. That will be relocated to the front.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092924;image)
Here I'm pulling the LED cable from under the long HV heatsink and routing across to the other side of the chassis.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092928;image)
Next, this fan guard needs to be removed.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092932;image)
These two screws will be reinstalled. This change makes room for the tailpiece to butt up tightly against the back wall of the unit.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092936;image)
Next, I remove the mainboard. There are 4 screws; one hides under the AC plug at the back.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092940;image)
There are 2 screws that hold the pull handle on; they're tucked in pretty tight, but you can get to them without taking the fan out if you have these long skinny drivers.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092944;image)
At this point I take a moment to wipe the insides of the insulator sheets clean with alcohol and to attack fan and PCB with a natural-bristle brush to dislodge most of the larger dusties.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092948;image)
I install one end of the VSENSE Mod wire now as it's a lot easier with that insulator sheet out of the way. I'm using 26ga Teflon-coated wire left over from a Thermistor install on my 3DP. Waste not, want not.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092952;image)
This insulator sheet always comes loose when you disassemble. Cleaning with alcohol and then (after it's well and properly dried, duh) playing a flame very briefly over the adhesive will reactivate it for a bit...
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092956;image)
...so I can reapply it to the side of the fan where it belongs. Yeeg; looks like I missed another spot while dusting with my paintbrush. Bad TinkerDwagon!
![Evil >:D](https://www.eevblog.com/forum/Smileys/default/evil.gif)
Now to reinstall the 4 mainboard screws.
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092960;image)
Now it's time to do the final routing of the LED cable around the other side wall and down into the recess for that one screw. This will allow me to...
![](https://www.eevblog.com/forum/projects/dell-aa23300-server-psu-mod-conversion-to-14v-1v45a-fixed-bench-supply/?action=dlattach;attach=1092964;image)
...reinstall the cover and screws. This last one stays out; that screw hole will be used for the nosepiece.
*CONTINUED IN FOLLOWING POST*