My HomeBrew / Converted Server PSU

[Buick Mackane]

Bit late to the party with this because i think most have already converted one of these, Anyhow this is my effort, 56 Amps / 12.5 volts, it's a Dell Model, Been laid in my cupboard for years, Sure it cost me a tenner brand new, There is a similar model which has an internal pot for adjusting the V-Out, This one doesn't, The connecting posts are cheapos, The thumb screws don't have metal inserts, The threads are cut into the plastic hence not much grip, But i'll just use ''Banana Plugs''

Volt meter is from my junk box..

[MrWeetabix]

I can't say I have enough confidence in my own abilities not to kill myself doing something like this, so you have my respect Sir. nice work

[Buick Mackane]

Cheers craig, Theres nothing to it really it's just a few wires

[Buick Mackane]

Plan is to run (an almost) homebrew station, using this power supply, My homebrew EFHW Antenna & ubitx HF kit transceiver, Might as well have been a homebrew transceiver by the time i finish modifying it

[Auldgeek]

Plan is to run (an almost) homebrew station, using this power supply, My homebrew EFHW Antenna & ubitx HF kit transceiver, Might as well have been a homebrew transceiver by the time i finish modifying it

Good stuff Jason. The ubitx is not a bad transceiver, but as you say it does need modified to get the best out of it.
That's half the fun mind you.

[Auldgeek]

My converted HP power supply still runs fine. While it's not essential, I would like to raise the voltage up from 13.2 to 13.8. It's an easy mod, but haven't had the time. One of these days!

[Buick Mackane]

Plan is to run (an almost) homebrew station, using this power supply, My homebrew EFHW Antenna & ubitx HF kit transceiver, Might as well have been a homebrew transceiver by the time i finish modifying it

Good stuff Jason. The ubitx is not a bad transceiver, but as you say it does need modified to get the best out of it.
That's half the fun mind you.

Main issue with my V4 ubitx was the RX Audio drew, Could hardly hear it even with a speaker pressed against my ear, Installed an LM386 Audio amp, But even that wasn't enough had to boost it with a pre-amp ahead of the LM386, Tons of volume now, Next job is to swap out the BP Relays with axicom relay's

Also need to swap out a few inductors and replace them with 1210 SMD inductors, But canny find any

[Buick Mackane]

The output of this power supply is quite dirty, Lot of birdies on 10 / 11m. No big problem though as i rarely work those bands.

[Chrissy MI7XCD]

Hi All, I know Ive just signed up to this forum but saw this and thought if I can help shed some experience using PC PSUs, as mentioned they have a really dirty output and am most certainly switch mode PSUs, ones you find in Waters and Stanton have additional filtering as sold for Radio hobbyists but theyre still not ideal.

The switch mode design basicaly has a reference point and its constantly cycling adjustments many, many times a second which gives loads of RF spikes. I'm also in the market for a PSU at the momment as I want to go homebase again, but Linear (Transformer type) PSUs would be the way to go. Theyre just a large rectifier and simple design with clean output, theres a few videos on youtube comparing the PSUs if you have a look.

Hope any of that helps, sorry to poke my two pence worth in (-:

[Buick Mackane]

Ok, The Mydel supply i talk about in this thread has a rather dirty output so i decided to get hold of an HP - 1200 WATT ''FB'' supply, These are supposed to have a clean output, Although iv'e not tested it yet as ive only just modified it,

The stock voltage on these seems to be round about 12.3 Volts, A resistor of approx 22k on the regulator brings it up to 13.66 volts (I used 20k) Then 110k on the over-voltage circuit should give a trigger limit of approx 14.2 volts, I had to parallel 2 resistors to get the correct value, Quick tweak of the voltage adjustment potentiometer brought it up to 13.8 Volts..

Best to use SMD chip resistors, But i don't have any and couldn't see them even if i did The resistors i used are pretty small but look huge against the SMD Components..........


A real dexterity test, A magnifier is a must as is a steady hand, If you like your vodka don't even attempt it A small needle type soldering iron tip is also a must..

All information on the mod is detailed in the link below, For the ''Start up'' mod you can do your own research, Plenty info online and on youtube

NOTE this is the ''FB'' Model........Cost me 11 quid delivered, Should be good for approx 70 amps,, NOTE this is a version 2 PCB, The V1 PCB varies slightly

https://ke0ff.github.io/hpsc/DPS-1200FBA_mods.pdf

[Buick Mackane]

Oh aye there's a piece of cardboard insulator that covers the PCB, You need to peel it back and hold it with tape to access the board, Just as your ready to solder the tape gives way and the insulator comes pinging up, Really annoying, Like a game of Buckaroo

[Buick Mackane]

Well this badboy likes to trip @ 13.8 volts, Strange as i have extended the range of the over voltage protection circuit, Problem is we don't really know the history of these units, They have probably ran round the clock for years

[Buick Mackane]

Well ive had a lot of headaches with this PSU, Turns out it trips if turned on and off quickly, Left on its fine & dandy, After all these are designed to run 24/7

Binding posts added and an on / off switch, And resistors fitted a bit more tidily ..Running 100 watts FM on my auld icom 706 the supply doesn't bat an eye lid, Bang on 13.8 volts loaded or unloaded..


Finally done

[Buick Mackane]

Just converted another one, This time i soldered the banana sockets to the power strips, But unless you have a powerful iron i wouldn't recommend this method, Mine is 50 watts and it took me ages, The first one i done i bolted the sockets on, But my drill bit is blunt hence this one i had to solder them on.

There is no real point adding an on / off switch to the power supply as even in the off position the fan still spins, I covered all exposed pins in silicon as the pins are very close together. And could easily short if a tiny speck of metal was to fall on them

I got both these supplies for £20, But they've since been snapped up as drew auldgeek bought about 10 of them

And as far as i can tell the output on these is very clean

[Auldgeek]

I got both these supplies for £20, But they've since been snapped up as drew auldgeek bought about 10 of them