I needed a second 16mm spigot with a M8 thread for mounting a light on a universal clamp. Since I had some brass bar stock around I figured I just machine one quickly.
Result Mine (right) and the commercially available one (left).
Quickie: 24V AC & Unregulated DC Power Supply
Quickie: 24V 1.5A Automotive Power Supply
Quickie: New paint for a Karl Klein DNG 6-22,5
I recently got this Karl Klein DNG 6-22,5 blower (22 m3/min) I want to use for dust extraction. Unfortunately the seller spray painted the whole thing with zinc spray w/o telling or asking me.
This is what I got out of the box: It appears that they at least stripped off parts of the old paint (maybe even sand blasted it?) but like I don’t like this look. So I gave it a quick new paint job, first I removed some of the zinc spray where it was not sticking properly.
Repairing a Siemens Schuckertwerke AC Motor
Disassembly Te screws of the bearing covers were completely sheared off, probably from vibrational damage.
New bearings Replaced the old bearings with new SKF 6200-2RSH ones.
Odd screws The screws holding the bearing cover were of an odd dimension, either imperial or something like M3.5.
I decided to rethread the inner plate to M4, so I can use standard screws. To do this I used a 3.5mm reamer to clean up the hole and re-threaded it to M4.
Voltcraft Power Supply Maintenance
I got a couple older power supplies from the Voltcraft brand, so I decided to clean them up a little bit:
12V 2A - Replacing Selenium Rectifier This unregulated unit had a selenium rectifier that started smelling a bit sweetly, which is the smell of impending failure. I replaced it with a silicon rectifier and also added a short circuit current limiting resistor, as I dunno whether the transformer is short circuit proof.
±340V, 170V DC Power Supply
Built this the other day to have a more accessible higher voltage DC.
The circuit is straight forward, a voltage multiplier giving ±340V off the 230Vac secondary of the transformer and another a half rectifier from the transformer’s 115Vac secondary to also provide 170V. I also added a small neon indicator to show whether the two main reservoir capacitors of the ±340V are still carrying a charge. The output is limited with power resistors.
1.25kV High-Voltage Power Supply Mk2
I decided to redo my old 1.25kV PMT Bias Power Supply. In particular I wanted the supply to run without a central power supply and added a small transformer and linear regulator so I can run it off mains. I also replaced the TNC connector with two safety 4mm banana connectors. The voltage divider for the multimeter is now on the HV board itself, rather than floating in the air.
Repairing a SE.306.1-2 Power Supply
I recently got this old power supply in an untested condition. It has an unregulated -24V DC output, as well as a regulated -14V output, cumulative 500mA max.
It is not really suitable as a laboratory power supply, as over current protection is done using a fuse on the secondary transformer side. A pretty neat feature however is the overload indicator, if the unregulated voltage rail drops too much it will light up way before there is a risk of the fuse blowing.
Gossen T4 80 1 Capacitor Replacement
I recently got this 80V/1A Gossen (SIEMENS branded) T4-80-1. It was in original condition and some of the capacitors did not look quite so good.
Cable grommet The rubber cable grommet started to become oil after all these years, so I cut it out and replaced it with a new one after cleaning the mess up.
Inside Look Some picture of the inside, I really like the manually wire wound power resistors.