HRD+ 74259 Daughterboard verified good

The subject says it all, really. I got ahold of a couple of 74LS259D SMD chips, soldered them into the adapter board, and replaced the ‘259 stack in the HRD+ with the daughterboard.

Since nothing ever works correctly the first time, I botched a solder joint on one of the chips and spent an hour with a microscope, a schematic, and a continuity tester to track down the problem.

Anyway, it works. Eagle .sch and .brd are here. Enjoy.

About Chris Kobayashi

I'm a security systems engineer, specializing in UNIX, network, and physical security. I'm in Tokyo, and I'm mostly retired now. I'm well-versed in both electrical and software engineering, with a particular interest in old computers and game consoles. You can contact me here.
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