This repo documents additional explorations into the reverse engineering effort of an Apollo-era printed circuit board assemly that Skyhawkson obtained earlier this year. See his project at the original repo.
work in progress, still documenting the process and observations check again in a few days
This is an interface board for reading sensors such as strain gauges. It features a precision voltage source to excite the bridge. It also has a differential amplifier to scale up the sensor voltage and proportionally drive an output load. The output stage has an enable pin, suggesting that multiple card outputs may be multiplexed into one analog to digital circuit card. That makes sense, since scanning through a bunch of sensors over and over again makes sense in the context of running through test sequences.
Maybe.
Schematic (PDF)
Reverse Engineering an Apollo-Era Circuit Card
https://github.com/Skyhawkson/Apollo-Era-Card-RevEng/tree/main
