Gossen Konstanter 2 T1 K 20 B 0.5 teardown

[Nauris]

My old power supply got pretty much tied up powering a motor in the workshop, so I needed a new one for my lab.
Come to realize all good new ones were sort of pricey, but then I found this one on Ebay.de with just 20 mins remaining.
Ended up with 36€ + 16€ postage.

A Gossen Konstanter 2 T1 K 20 B 0.5
20V 0.5 A and dual output, that is very much appreciated feature.


And it works! Meters are pretty much spot on. 2nd channel potentiometer is a bit jumpy, but I hope it is just because of lack of use.


Not too much components in there.


Pass transistors are 2N3055, like you could find in a nowadays power supply.


Green transistors! (BC251)
There is even an integrated circuits in it, LM304 made by SG in 1975 and 1972. Newer one looks bent, maybe someone has replaced it?

So that makes it about 45 years old. Even the capacitors are apparently good, as it does not show noticeable ripple. Output tends to drift some
tens of millivolts with time thought.

[threephase]

Nice find, totally different to what they make these days.

Kind regards.