I recently got this old ERSA 80 the power cord of which didn’t look great. It had been sitting in a basement probably for 40 years.
I decided to replace this with a SIHF silicone cable, those are somewhat heat resistant. Certainly better than normal PVC cords. I kept the old Bakelite Schutzkontaktstecker, as it is still fine.
Sub-distribution panel for my datacenter
Similarly to my workshop I decided to built a dedicated distribution panel for my data center installation. Once I redo the electrical installation in the house in the coming year, this panel may end up being partially redundant (i.e. surge protectors and RCD) but I guess redundancy is better anyhow, rather have two breakers trip at the same time than one failing to do so.
1, 2) Main RCD 25A 30mA A Type 3) Main circuit breaker 16A B type, 4,5) Branch breaker 10A B type, 6,7,8) Branch breaker 6A B type, 9) Single phase meter, 11,12) Surge protectors
Microscopy Insights #6: Chrysoperla Carnea
Stereomicroscopy images of a Gemeine Florfliege (Chrysoperla carnea s. l.)
All images taken with a Sony Alpha SLT-A77 on my MBS-10.
Dragonfly visit (Aeshna Cyanea)
I was recently soldering at night on the balcony and got visited by a dragonfly which appears to be a Aeshna Cyanea (Blaugrüne Mosaikjungfer).
It slept over night on my desk lamp and flew away in the morning.
Gossen Pantam Konstanter T2 33 015 Repair #2
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.
Gossen Pantam Konstanter T2 33 015 Repair #1
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.
Measuring mechanical vibrations of watches using a Piezo element (Part 1)
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.
±5V 300mA Bipolar Desk Supply
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.
Test Tube Rack Restoration
I have this old test tube rack my mom gifted to me on my birthday in the early 2000s, it sat on the balcony for years which can be examined by the clear signs of prolonged water contact. So I figured to restore it again. I sanded it and applied new wood glaze.
East German Watchmaker's Drill press
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.