Mini bed level failure

Purchased used mini. Worked great for a week or so. Previous owner stressed to me to keep nozzle clean. I was keeping it spotless. with a brass brush :pensive: Anyway, now it does its wipe fine, touches 1st washer fine, moves to 2nd washer but moves up 1 inch, moves to third moves up another inch, but never touches another washer besides the 1st. then tries to print while really pushing into bed. i replaced nozzle, checked all wires. Do i need new board? thanks

Have you tried upgrading firmware through CURA just in case you caused a sort using the brass brush corrupting the firmware?

Just a thought

The input line sensing nozzle<->washer contact may be getting a spurious signal. This could cause it to register a corner height as too high. (I’m not running marlin/lulzbot firmware, so I don’t recall what checks are in place to avoid this.) You should manually verify that the probe can be consistently be read as open and triggered in all 4 corners. If not, you need to check the connections between the nozzle and board and bed corners and board.

Also, don’t clean the nozzle with a wire brush. Use a green scotchbrite pad. Lulzbot leveling works by sensing electrical contact between the nozzle and a corner washer. To do this, the nozzle is connected to an IO pin on the microcontroller that is rated for 5V @ something like 30ma current. The heater cartridge that heats the hot end pulls ~2A @24V. When cleaning the nozzle with a metal brush, it’s easy to make contact between exposed wires on the heater element and the nozzle. This can easily damage the sensor input pin—potentially causing it to provide inaccurate input values.