Avionics + mil-spec teardowns

Got another second copy of the CPU board from the probable-rocket-engine-controller to decap all the custom ICs and get an idea of what's going on, with die imaging by Ken Shirriff:

https://www.eevblog.com/forum/projects/avionics-teardown-looking-at-some-mystery-rocketdyne-boards/msg5508781/#msg5508781

Looked at some L3 Communications boards from a mystery military/aerospace radio system, and opened a couple high-frequency VCO modules:

https://www.eevblog.com/forum/rf-microwave/interesting-unusual-rfmicrowave-boards/msg5495731/#msg5495731

I partly reverse-engineered a couple measurement & interface boards from a late-80's satellite-microwave-comms terminal used on submarines:

https://www.eevblog.com/forum/projects/reverse-engineering-misc-avionics-(part-3-raytheon-eas-diehl)/msg5491783/#msg5491783

Newest one I've opened so far - here's a Remote Interface Unit (aircraft version of an I/O expander) from 2004:

https://www.eevblog.com/forum/projects/reverse-engineering-misc-avionics-(part-3-raytheon-eas-diehl)/msg5467831/#msg5467831

I traced the schematics of some mystery RF boards from the early 80's, and looked at hybrid circuits inside some metal cans:

https://www.eevblog.com/forum/rf-microwave/interesting-unusual-rfmicrowave-boards/msg5460263/#msg5460263

Posted a quick teardown & analysis of a frequency multiplier from an AN/APQ-120 radar: https://www.eevblog.com/forum/rf-microwave/interesting-unusual-rfmicrowave-boards/msg5412884/#msg5412884

Includes an impressive number of trimmer capacitors, and an old microwave diode

Added a partial reverse-engineering analysis of a late-70's fire control computer from a tank, inc. notes on radiation-hardening electronics.  More descriptions of digital logic & power supply to come.

https://www.eevblog.com/forum/projects/reverse-engineering-a-late-70s-fire-control-computer-from-an-m1-tank/

68000 CPU on a mid-90's board that may be from specialized navigation/training(?) equipment; a giant ASIC contains many mysteries.

https://www.flickr.com/photos/147639706@N02/albums/72177720314646603/

Finally got around to finishing a writeup about the NZ-920 navigation computer I got as scrap a while back.  Unfortunately wasn't able to do any real circuit tracing here due to a combination of densely-packed multi-layer boards and conformal coating, but figured out some things about it just from looking, although mysteries remain.

https://www.eevblog.com/forum/projects/avionics-reverse-engineering-honeywellsperry-nz-920-navigation-computer/

Final installment of the Rocketdyne board analysis: this one's much clearer about what it does and how it works, despite a few minor mysteries.

https://www.eevblog.com/forum/projects/avionics-teardown-looking-at-some-mystery-rocketdyne-boards/msg5279293/#msg5279293