Prelude Vfd Power Supply

About the project #

a year or so ago, one of my pals purchased waaaaay too many honda preludes at an unfathomably cheap price. when we got them running, i noticed that the fuel and temperature guage was a vacuum fluorescent display (aka VFD) technology, and most of the gauges across all the cars didn’t seem to function. my curious ass decided to jump into action and investigate; long story short, i found that the printed circuit board (aka PCB) responsible for transforming and delivering power to the VFD had shit the bed and most of the electrolytic capacitors had leaked everywhere. as a result, the traces on the PCB had burned up and the gauges didn’t work anymore (or worked poorly).

i saw this as an opportunity to learn some skills and gain some new knowledge along the way, so i took it upon myself to reverse engineer these boards and try to redesign a new replacement. in the process, i dived very deep into a rabbit hole and found this is a very very very common issue in these vehicles and there wasn’t a nice solution available.

my goal for this project isn’t to create a 1-to-1 replacement; instead it is to understand how honda intended to originally design this circuit, and create a new design that could function in the same manner. building a cheap replacement isn’t the goal - i am seeking to learn how to design and build PCBs, and to design some functional solution - even if it’s overcomplicated (foreshadowing).