Avionics + mil-spec teardowns

Here's some boards of unknown function from the mid-90's: https://www.eevblog.com/forum/projects/avionics-teardown-honeywell-aerospace-mystery-boards/

I couldn't reverse-engineer a full schematic, but looking at all the part numbers lets us at least learn some things about them (plus they look really nice).

Here's an analog data acquisition board from 1982 that I suspect is from an aircraft Heads-Up Display: https://www.eevblog.com/forum/projects/reverse-engineering-misc-avionics-(part-3-raytheon-eas-diehl)/msg6207329/#msg6207329

...and a closer look at the ADC hybrid module it's built around: https://www.eevblog.com/forum/projects/de-capping-circuit-analysis-of-hybrid-modules/msg6207351/#msg6207351

Here's a strange one, with reversed IC pinouts and other strangeness - sure is nice to look at though: https://www.eevblog.com/forum/projects/reverse-engineering-two-70s-military-digital-logic-boards/msg6171713/#msg6171713

This large assembly only contains 3 MIL-STD-1553 serial channels, plus some counters.  Surprising how much board space this used to take up!  https://www.eevblog.com/forum/projects/avionics-teardown-engine-controller-boards/msg6143931/#msg6143931

Here's an interesting module that generates an (audio?) waveform from a ROM, at a programmable frequency, using some fun symmetry tricks to reduce the memory needed: https://www.eevblog.com/forum/projects/reverse-engineering-two-70s-military-digital-logic-boards/

Lots of interesting things to see in this airborne telemetry unit from Hughes Aircraft: early ICs in gold flatpacks, tiny ceramic PCBs, and tightly-packed 3D RF circuitry.

https://www.eevblog.com/forum/projects/avionics-reverse-engineering-60s-hughes-telemetry-unit/

Interesting construction here, with an extra-thin assembly based on a flexible PCB and a thin metal backing: https://www.eevblog.com/forum/projects/reverse-engineering-misc-avionics-(part-3-raytheon-eas-diehl)/msg5998709/#msg5998709

Here's a couple engine control computer boards from a commercial aircraft: https://www.eevblog.com/forum/projects/avionics-teardown-engine-controller-boards/

Here's a "deflection pre-amplifier", with a lot of textbook discrete-transistor amplifiers, plus some interesting twists on current-source biasing: https://www.eevblog.com/forum/projects/reverse-engineering-some-navy-(submarine)-video-boards/msg5940508/#msg5940508

Looking at the first of two video amplifiers, from some kind of 80's marine electronics, possibly from a submarine combat data system: https://www.eevblog.com/forum/projects/reverse-engineering-some-navy-(submarine)-video-boards/