Problem with z axis repeatability

I should preface this with: the R2 with the problem is my oldest R2, from 2018 and has run 24/7 since its purchase.

Over the course of a month one of my R2's started having problems with the z axis repeatability resulting in many unusable parts. Then the z axis switch died. I replace the z axis sensor ( a real pain in the butt ) and while I was at it I removed the 10uf electrolytic cap on the IR board and replaced it with a much lower impedance stacked ceramic 1uf cap.

The result was I was back in business. I can not really separate which was the fix.

If you are getting bad z axis repeatability consider doing one change and then the other.

I just did the capacitor change to an IR board on another machine.. It is interesting that in both boards with the stacked ceramic cap the nozzle got about .2mm closer to the bed. I do not know what this means, but both IR boards are working very well.