ellindsey Posted May 26, 2022 Share Posted May 26, 2022 Several decades ago, I was exploring a junkyard where I found a pile of industrial-looking circuit boards in a pile of scrap, and on a whim bought some of them for a few dollars. They've been in my parts bin ever since. Lately I've decided to try and research what these actually were, in case they were ever anything interesting. There are two different types, one which appears to be a CPU board, and one which is a keyboard and display board. I'm pretty sure they used to be connected with the ribbon cables which are now cut off. The CPU board has a TMS9995 CPU (in the lower left, with the text nearly unreadable), two TMS9901 interface chips, three sockets for EPROMS, a pair of N82LS135N PROMs, a pair of ICM7218 7 segment display drivers, a DS1220 battery-backed SRAM, a fair number of optoisolators, and various glue logic chips. The display board has a 16 button membrane keyboard, and a lot of 7 segment LED displays. It also has multiple voltage regulators on heatsinks on the other side of the board. On one of the controller boards, the EPROMS have labels that say "PSE&G". PSE&G is one of our local energy utilities companies, which suggests that these boards were probably part of some energy monitoring or distribution system. The only other label I can find on these is here on the back side of the display boards. Megatran Industries is a local electronics manufacturing company who make custom systems for the power industry and has been around since 1968, so that's probably who made these boards. That's about as far as I've gotten with these. If I feel really ambitious I might try and trace out some of the circuitry and connections between the board to confirm that these actually went together. I really doubt that any of the components on here are salvageable, it's all pretty badly corroded from being stored outdoors in a junkyard before I found them. My wife and I are trying to de-clutter the condo and get rid of anything we don't use, so these will probably end up going on the free table at the next local vintage computer swap meet. 5 1 Quote Link to comment Share on other sites More sharing options...
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