So I recently found this while clearing out the workshop of someone: It is a charging indicator for mining lamp charger racks, in partcular for Oldham-Arras lamps. It still had the bus bar mounting clips attached to it. So of course with this sitting around, I decided to built my own mining light charger. NiCd mining lights were charged using constant voltage, since they were used all ~20h with the charging requiring around 14-16h, so the time of the cells being charged and venting was kept fairly low.
Circuit Nothing much to say, it’s fairly standard. The relays are switched using BC517 darlington transistors. The unit is powered using a 230V to 12V AC/DC SMPS, the 5V for the ESP8266 board is derived from a standard LM7805. I used a WEMOS D1 I desoldered from another project, unfortunately a couple of the output pins didn’t work (probably damaged an internal trace while desoldering). So I used some wires to connect the signals to the pins that are working.
This is part of my Frequency Standard System. Oscillator VEB Narva 10Mhz The 10MHz TCXO itself is from east Germany made by NARVA. According to the data sheet it has a tolerance of ±2e-6, an aging of ±1e-6 and a thermal precision of ±3e-6. Given the timestamp of 1983 on it, it will have a deviation of approximately 3.7e-5 at this point. The TCXO power circuit consists of a 555 timer with an ON-delay of a couple of seconds to ensure the supply has stabilized.
So with the built of my watch amplifier recently I got to question myself on how do I get a stable clock reference signal?. So I decided to build a frequency standard system. Unfortunately I don’t have a Rubidium reference right now but I decided to build everything in modules, so I can swap any part of it with a better or improved variant once I obtain the parts to build them.
I looked at several other open source library software suits with an OPAC but they were either too much of an overkill or unmaintained for a while. My main requirement was the software to support MARC. I eventually decided to go with the traditional open-source ILS Koha. Installation I decided to install Koha in a LXC container with Debian running on my virtualization server which on itself runs Alpine Linux. So first I created a container:
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.
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
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.