This is part of my Frequency Standard System. This board is a direct implementation of the circuit outlined in this article by Gavin Watkins. So there is not too much to say about it, the article explains the working. I used the unused gates on the 74AC00 as output drivers for the 50Ω BNC.
As mentioned on my MBS-10 post the power supply of the ringlight I have for the former isn’t quite up the the safety standards I’d like. It was one of the cheaptest I could get and the quality of the power supply matches that. So I decided to built myself a new one! It’s an unregulated 12-15V power supply with an adjustable current limiter consisting of a TIP41C transistor. I used a lot of hot glue to secure the front panel components, as they wouldn’t probably hold on the plastic panel.
For the keen observer, the picture on my last post about the SUN Netra X1 showed a couple suspicious capacitors around the processor. Two of them already started venting, so I figured to replace them before the short out and damage the mainboard. I also examined all other capacitors, including in the power supply and those all still looked fine. The broken capacitors in question are SANYO 1500uF/6.3V I replaced them with Würth 1500uF/10V capacitors (WCAP-ATUL 860040275011) which happen to have the same via spacing and diameter.
My old SUN Netra-X1 with an UltraSPARC-IIe+ lately had some bad sectors in it’s IDE hard drive, an old Seagate Baracuda 40GB. I found some IDE to SATA protocol converters online and figured might as well give it a try. Would be nice being able to put SATA hard drives or even SSDs into my old SUN machines. Bingo! wd1 at pciide0 channel 1 drive 0: <INTEL SSDSC2CW120A3> wd1: 16-sector PIO, LBA48, 114473MB, 234441648 sectors wd1(pciide0:1:0): using PIO mode 4, Ultra-DMA mode 2 I decided to do a reinstall of the system while I’m on it and booted bsd.
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.