found something interesting in the net. a detailed guide, how to convert a PC-powerpack into a laboratory-powerpack. http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply 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.