Y-Min triggering, any suggestions?

Hey guys, so my problem started yesterday afternoon, my printer started making a weird noise, so i came to check, the build plate was all the way in front, not moving as usual. So i stopped the print to check. So i moved the build plate to the middle and tried to home it, but all it did was move a little bit in front.

I contacted customer support who diagnosed it as perhaps a bad switch or a bad cable chain after some tests.

Here’s the thing, so i took a multimeter, disconnected the connectors from the switch, and manually clicked it, to test if there’s a connection. It worked, so yay, its not the switch.

I then connected the wires back, and took out the connecter to the board, did the same thing at the wire ends, and it works too! (beep on my multimeter when i click the switch).

So, ok, neither the cable nor the switch are at fault, so leaving it unplugged, i ran cura and entered in M119, turns out the z-min is still being triggered, which prevents the bed from moving in the negative direction.

Any suggestions as to what i can try next? I’m really hoping not to send it back in for repair as shipping from here would be burning a hole in my wallet…

If Z min is being triggered when the nozzle isn’t in contact with a disk, you have a short somewhere. Or something plugged in wrong. Or something jammed in the Z axis switch that does nothing but might actually do something. Check that the disks are down and tight, and that the nozzle sensor wire is in the correct spot and tight, and the under bed wire mount is intact and installed correctly on its ground post.

With the Mini powered on but not heated measure from the extruder heater block to the aluminum bed plate with the wires connected to the RAMBo. I it should read about 5 volts, and if not and you are reading around 0-3 volts. Contact support again.

Z Min is the contact/switch for the bed leveling, but if it has shorted it can cause Y to fail first before flagging that Z has failed.

Thanks, I’ve done some tests, and finding that it is 99% a board problem, i’ll probably have to RMA it back according to customer service.