Continuing from the previous I’m going to document repairing the second Gossen Pantam T2 33 015 with this entry. Shorted ASY14 transistor This one had an odd behavior, where it wouldn’t built up voltage and when cutting power to it there would suddenly be a voltage spike on the output. I first suspected a broken capacitor (as with the other most electrolytic capacitors didn’t look too good). So I checked for shorts on the capacitors, and immediately found one but not on a capacitor but between the base and emitter of one of the large ASZ15 transistors.
I recently got two Gossen Pantam Konstanter 33 015 lab supplies from the mid to late 60s as shown above. Both of them are their own can of worms and need some fixing. The following describes how I fixed one of them , I’ll do another post once I fix the second one. This one is peculiar in that someone already had a go with it and “fixed” some of the things, multiple parts have been replaced at some point and there are clear signs of amateur soldering, in that wires have been touched and scorched by a soldering iron.
So the other day I wondered whether it is possible to measure mechanical vibrations of wristwatches using a Piezo element (piezoelectricity). I did a little bit of research and found several people who already built something like this. I decided to go with Stefan Vorkoetter’s excellent design (also checkout their software watch-o-scope). Coincidentally I had the same or at least a very similar case as the one shown on their instructions, so I figured I use it for mine as well.
Schematic I decided to go with a fairly standard 7805/7905 supply with protection diodes, nothing really worth mentioning here. [yes, I know four point cross connections on schematics are not in accordance to DIN schematic standards] Construction Nothing really worth mentioning with the construction either, other than that the electrolyte capacitors were wobbly so I hot glued them to the board to ensure they don’t eventually break off with oscillations from the transformer.
I got this old and interesting east German drill press. It was in working condition but I decided to service it a little in order to make it last longer and do some preventative maintenance. What’s really interesting is that this drill press uses a Centrifugal governor for speed regulation. Work piece Table The most interesting thing is, that contrary to other drill presses, where you have a pinole that lowers the drill this drill possesses a table that raises the work piece to the spindle.
Changing outlets of a broken extension cord I have an old mangled extension cord, that has been sitting around, so I figured I fix it so I can make use of it again. The Schutzkontaktstecker was falling apart and the cable had a cut that someone fixed with some tape. I cut off the broken part which fortunately was quite close to one of the ends and replaced both the plug and socket with a TAURUS 2 plug and socket from PCE.
I acquired this Paul Waechter microscope a while back. It was in quite a rough shape, most of the brass plated parts had the brass rust off or corroded. I decided to only fix the severely broken parts and keep as much of it original, as possible. I’m generally not a fan of making old things look new and shiny again, old things have the right to look old and used.