Auto Leveling Failed Again: 0V between nozzle and washer

As I’ve noted in some of my other posts, I’ve had auto leveling problems ever since I got my Mini. I’ve worked around it, and I thought it was due to worn-out wiper pads, plastic on the washers, etc. etc. etc.

The extruder blockages that I’ve experienced in retrospect are also due to inaccurate leveling - the nozzle gets pushed down really hard on the washer resulting in an artificially large negative Z-offset which blocks the nozzle and causes filament build-up inside the extruder until it gets to the heat break and hardens.

But to my immediate problem: I’ve always had problems with the first washer, but now I get problems on the other washers as well. I used to be able to measure 5V between the nozzle and all the washers, but now I don’t get any voltage at all.

Is the 5V available all the time? or only when probing? What wiring do I need to check?

The newer firmware only enables the pin during probing now, so you will see nothing unless you are probing the washers.

Definitely getting 0V even when probing. Sometimes I suddenly see 4.xx V and then probing succeeds but that’s the exception now. Chewing up so many wiper pads…

Resolution: broken Z-min wire to the build plate. Didn’t bother to thread the new wires (I used 2 x 18-awg stranded for redundancy) through the cable carrier, just zip-tied them to the outside.

I was really expecting a more reliable experience from what is ostensibly an American brand. Not a happy camper.