Good afternoon everyone: I take this opportunity to introduce myself in my first post and thank you in advance for your help. I have an old adjustable source, which will take a long time without being used. It is 0-30v and 0 to 5 amps. To begin with, it does not exceed 26 v in a vacuum, nor does it fall below 2 v, and if I regulate the output voltage for example to 12 volts and subject it to a consumption of 2 amps, it falls apart. It falls to 7 or 8 volts and the intensity also goes through the floors. It's simple, nothing commutated or the like. Its transformer, its rectifier, filter and regulation with a pair of Motorola 381 TO-3 transistors. Of the transformer I do not suspect, because it is left over, nor of the pair of transistors, I lean towards the capacitors, a couple of 4700uF and 63v, which I believe that over the years they have been able to dry. The bad thing is that I don't have a capacimeter to verify it yet. What do you think? Could it be that I had a semiconductor or other KO component with these symptoms? regards

..... and the pair of transistors. Maybe I had a bad weld or something apart, because when I solved all the components that I had removed, it worked. It makes me a little angry not to know exactly what was wrong (typical in electronics this haha) but what matters is that it works. Now I set 12v and ask for 4 amps and the tension remains. Well, I post it in case it suits someone, SOLVED. And thank you