Permanently fix a broken jumpy Mercedes 300D W123 turbodiesel tachometer

In this short video I present possible fixes for a non functioning or jumpy tachometer on a W123 W126 or W116 turbodiesel made by Mercedes during the 1980s. The electronics in these cars was designed in the 1980s with then current tech that has aged out after forty years. I give some background on how the system works and the different components that typically fail in these cars. I am the designer of a updated digital tachometer amplifier that I designed in Spring 2021. Replacing the amplifier with a rebuilt unit or my new unit will fix 95% of the tachometer failures out there. Check out my other video for details about the all digital tach amp technology. Finally I present some information about late W123 turbo cars made from 84-85. I do not sell a solution for these cars. Fortunately 100% of the problems with these models are broken wires and bad connections between the sensor and dash gauge. These are easy to fix things that can be done at home for free.