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• IBM Federal Systems Division Oscillator/Audio Module

  Don Straney • 11/01/2025 at 17:14 • 0 comments

  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/

• Late-60's telemetry unit teardown

  Don Straney • 08/20/2025 at 04:53 • 0 comments

  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/
  

• Mystery flex-PCB card

  Don Straney • 08/03/2025 at 00:48 • 0 comments

  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

• Aircraft engine controller boards

  Don Straney • 07/06/2025 at 19:23 • 0 comments

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

• Naval analog video boards (#2)

  Don Straney • 06/08/2025 at 02:04 • 0 comments

  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

  
  

• Naval analog video boards

  Don Straney • 06/06/2025 at 21:53 • 0 comments

  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/

• Mystery optical-communications board from aircraft

  Don Straney • 05/10/2025 at 21:06 • 0 comments

  Not sure what it's from, but it seems to be for optical communications - includes multiple interesting hybrid modules: https://www.eevblog.com/forum/projects/avionics-reverse-engineering-optical-communications-card/

• Navigation Display boards

  Don Straney • 04/11/2025 at 12:36 • 0 comments

  Lots of shift registers & 7-segment decoders, plus a dimming circuit with a discrete-transistor feedback loop: https://www.eevblog.com/forum/projects/avionics-reverse-engineering-navigation-display-boards/

• Mystery Litton military boards: part 2

  Don Straney • 11/12/2024 at 15:21 • 0 comments

  Let's take a look at a signal generator board, with a lot of programmable logic, RAM, and 5 separate DACs: this might do DDS waveform generation for radar transmit pulses.

  https://www.eevblog.com/forum/projects/reverse-engineering-some-litton-military-boards/msg5711141/#msg5711141

• Mystery Litton military boards: part 1

  Don Straney • 11/10/2024 at 01:39 • 0 comments

  Take a look at some super-shiny gold & ceramic, which turns out to be a high-bandwidth parallel data acquisition system.  There's a lot of fast op-amps, comparators, and ADCs, plus a dynamic offset-correction circuit with a specialty sample-and-hold chip, but the overall function is still a bit of a mystery (I suspect either imaging or radar).

  https://www.eevblog.com/forum/projects/reverse-engineering-some-litton-military-boards/

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