@Buco posted:I have a "dead" circuit board in my Z Controller in that there is now a constant 18V AC output through the outlets (red & black plug connections).
As soon as I turn it on there is 18V going to the track, and no matter what I do, there is no longer any control of the voltage to the track through the speed knob on the fascia panel.
Can I repair this myself using components sourced from my local electronics store (Jaycar)?? YES, between gunrunnerjohn and my post are the 3 main components that control the output.
If not, I can always use it for "fixed voltage" to power accessories on the layout......uncoupling tracks, switch motors etc. -YES, but fixing could be relatively simple.
Known failure mode (output shorted full on), there is a chance the TVS diode is simply failed and that is why you are seeing "full" voltage output constantly. Just cut one leg. The purpose is to protect the FETs, and given it failed implies inductive spikes happened and could happen again. So ideally replace it, but simple way to make a non-functioning one repaired with a cheap and relatively easy fix.
