In a various spending spree of avionics I bought on eBay I have a radio control box for a Plessey PTR-1751 military radio, a common unit used in several aircraft including helicopters during the 1980s and 1990’s. The radio has 7000 channels across 25khz intervals as well as AM reception on 243Mhz for emergency use. It has a power output of 10 or 20 watts and is powered from a 28V supply. Now the main unit is missing and I only have the main control box which features a 5 digit “Numitron” display which are incandescent filament 7 segment displays, which are still preferred in some uses due to their readability in a variety of conditions including night vision goggles.
Electronics wise it consists of several circuit boards populated with mainly 4000 series CMOS chips, some PLL synthesizers, transistor arrays and a custom 40 pin IC labelled NOM402L made by Mitel semiconductor which is some sort of programmable logic array.
Here are some photos and a YouTube video of the teardown.
YouTube Video