Large Scale Central

A cheap powerpack

found something interesting in the net. a detailed guide, how to convert a PC-powerpack into a laboratory-powerpack. As i had left two of those LGB outdoor dials for DC, i decided on a slightly modified verson. just using the +12 and the -12 cables. thus i got a nice 24V 15 Amp trafo for my trains.

( the black box, i glued on the pack, started its util life as a napkin spender) at the first test it did power seven Stainzes (six and a motorized tender) at a speed, that is faster, than i ever plan to run my trains. at full throttle, the automatic breaker set in.

and for the fun of it, i now got a lab-powerpack too.

Interesting… but most power supplies have way more +12v than -12v… did you check the specifications of the amperage of these outputs first?

I see you have a minus 0 output, do you have a plus 0 output ( :wink: )


no. we just followed the steps given on that website, where i found that idea.
we tested, when it was connected to the track. as i wrote, 24 volt and 15 Amp.

on the box of the powerpack it said 15 Amp for +12 and for the whole pack a strength of 230 Amp.

--------------------------------------------EDITING - I MEANT 230 Watt!!!--------------------------

for the remaining dial (meanwhile i know, that it is a “rheostat”) i will take a stronger powerpack. maybe i get even more Amps on my 24 volt combination.

no, the “0” are both marked as minus. i did that as a permanent reminder for my forgetfullness. as you can see, i chose red for all “plus” and black for all “minus” so i have just to remember, that i should never connect two wires of the same color.

Good potential for DCC as the DC out is real “clean”. Can’t have “dirty” voltage when dealing with logic chips etc!

looking at your signature:
“With Eyes Wide Open & a Clear Mind, I will Improvise, Adapt and Overcome whatever the challenge.”
the thought crossed my mind, that this DIY pack is the proof, that the “clear mind” is just optional…

no, before you mentioned it, i never thought about the potential for DCC.

Cool. I just stripped a supply from a PC I tossed. Was wondering if I should keep it or toss it. Might try this.

I’ve never tried using one before because I figured the best I could get out of it was 12V. Never thought of using +12 and -12 to yield 24V. Like Greg said, I’d be really surprised if you can get much amperage out of one above 12V though. Normal specs for the -12V line are about .8 Amps.


That’s why they invented fuses to preclude the potential for nuclear meltdown! LOL! Some light reading. Spent quite a few years in a Power Products Aplications Lab at TRW.

Korm, what are the identifying marks on the P.S, if any?

Jon, using +12 and -12 i got exactly 15 Amps at 24V from the pack, marked 230 Watt. from the one marked 200 Watt it is 13point-something amps and 23point-something volts. (when no loco was running) rooster, no cloud signals on this project! the young man, who helps me with that project, told me that the packs got automatic breakers, that respond at 30 Amp. identifying marks?? what’s that? maybe you mean this? (the pic is from the weaker pack)

Kool! Rated 15A but they always are conservative by at least 25%!!!

Korm Kormsen said:
. . . and for the whole pack a strength of 230 Amp.
I seriously doubt that the power supply you show is capable of "230 Amp." The specs on the equipment tag are not clear on my monitor, but don't mention anything near that.

Are you trying to build an arc welder??

Happy (Really High Current) RRing,


I guess we all stand corrected for a potential typo! I knew from the get go that 230 Amp was meant to say 230 watts. But then again I am only an engineer by education and employment! Me Bad!

yes, my fault!

thanks to Jerry, for rubbing my nose into it.

i made a typo. the two packs i used were 200 Watts and 230 Watts. input 230 Volts AC output various voltages in DC.
the pic of the specifications table is from the smaller one. (i don’t want to dismantle the other again, just for a pic)

i just bougght a 300 Watt pack for 18$. rated as +12 with 19 Amps.
and the young man, who helped me with the first two, now is building another one with rheostat for +12 and -12Volts.

Good Stuff Korm! And to think I just junked two PC desktops that I could harvested the P.S.'s out of. For shame…Yogi Wallace would not be happy with me.

mike miller said:
Good Stuff Korm! And to think I just junked two PC desktops that I could harvested the P.S.'s out of. For shame...Yogi Wallace would not be happy with me.
yep, another of Murphy's laws. if one keeps something, it will never be used. if one throws something away, it would come in handy within fourteen days.
Korm Kormsen said:
rooster, no cloud signals on this project!
No fun in that! :)

if anybody should get the idea to copy this, i got warned in a german forum, that the LGB rheostats can’t stand more than 5 Amps.

for me that will be no problem, because no powerpack will power more than four stainz-type motors at any given time. (that should not amount to more than 4 Amps).
anyhow, i will put in 5 Amp fuses, to be on the safe side.

but it makes me think, that i should try to set up two rheostats per powerpack.

I have more than one of those waiting for duty.

There was so much power on my HOm layout back East (in my previous life) my buddies always teased me about having enough power to run half of the TTC (Toronto Transit Commission).

the above link should come in handy for those who also build (unintended) smoke units. :lol: :lol: :stuck_out_tongue:

I’ll bet the 24v output is not 15 amps… test it…

The picture shown earlier has the -12v at 0.8 amps… with the +12v at 15 amps.