This video features a teardown of a vintage avionics display unit, manufactured by Ferranti Defense Systems Ltd. (serial number 102). The unit is revealed to have a highly modular, dense construction, consisting of a card cage housing eight function-specific circuit boards. These boards, which include synchro amplifiers, digital data transmitters and receivers, data storage, and display drivers, are built with military-grade 54-series logic ICs, classic op-amps, and various transistors. The presence of numerous manual modifications ("bodges") suggests a low-volume production or prototype nature. The front panel's display technology is also examined, revealing a system that uses small, individually lit bulbs projected through what appear to be light pipes to create the various indicators, including a specific North/South waypoint display.
A Teardown of a Ferranti Avionics Display Unit
00:00:04 Unit Identification: The video examines an avionics display unit manufactured by Ferranti Defense Systems Ltd. It features a rotary switch, various indicator labels (PSU, BIT, CDU, etc.), three push buttons, and a circular rear connector.
00:01:14 Modular Card Cage Design: Upon opening, the unit is shown to be densely packed with eight individual circuit boards housed in a card cage, each with a specific function.
00:01:33 Board #8 - Control Synchro Amplifier: This board contains 54LS series logic ICs, a relay, and a classic 747 dual op-amp. The presenter notes it has the appearance of a prototype board.
00:02:46 Board #7 - Amplifier Synchro Output: This board features three identical power stages using complementary transistors (2N5153 and 5154) and a 747 op-amp to drive synchro outputs.
00:03:34 Board #6 - Digital Display Driver: Populated with numerous transistors, this board's key component is a 5448 seven-segment display driver IC.
00:04:30 Board #5 - Store Digital Data: This board is filled with logic ICs and transistors for data storage and features several "bodges," or manual post-production modifications.
00:05:29 Boards #2, #3, #4 - Data I/O and Lamp Drivers: The teardown quickly moves through the Digital Data Receiver (Board #3), Lamp Driver (Board #4), and Digital Data Transmitter (Board #2), which features a timing crystal.
00:06:24 Board #1 - Power Supply: The final board is part of the power supply, containing filtering coils and two TO-3 packaged power transistors for voltage regulation. This board also shows evidence of manual bodges.
00:07:23 Waypoint Display Assembly: A specialized, long display component is removed from the front panel. It is marked with N, +, -, and S (North/South) and is identified as the waypoint indicator.
00:07:47 Light Bulb & Light Pipe Illumination: The display indicators are not self-illuminated but are lit by small light bulbs. The light is projected forward, likely through a system of light pipes, to illuminate the front panel annunciators.