LDM #375: Boeing 727 EPR Indicator - Part 1: Teardown and Reverse engineering

This video shows technical details of an aircraft instrument manufactured by Spirent in the 90’s. This instrument is an EPR indicator, Engine Pressure Ratio. On this first episode there are two sections. The first one shows the internal construction. The second section shows the complete schematic diagram with explanations. The second episode will show the code disassembly and I hope the complete test of this unit using an ARINC429 test generator. 00:00 - Intro 01:05 - Teardown 02:54 - Interface board 03:35 - MPU board 04:57 - Power supply and stepper motors driver board 06:43 - Display board 07:40 - Preliminary test 10:15 - Display test Reverse engineering: 10:50 - MPU board 12:27 - ARINC429 Interface Board 15:50 - Luminosity control 17:39 - Power down detection 18:15 - Display board Schematic diagram: Blog: