Troubleshooting Z-axis Gantry

One of my Taz 6 printers stopped working a while ago. The z-axis gantry stopped going up and down. Not sure if it is the stepper motors, stepper controllers, motherboard, sensors, corrupted driver, or something else. Does anyone have any tips on how to troubleshoot this problem? Thanks.

Sometimes the Z stepper driver fails, but more often the gantry gets out of square, so it can’t go up/down.

Does it move at all up/down? With the machine off, can you manually twist the rods to raise/lower the gantry?

If the nozzle is near the bed, try putting an object between the nozzle and bed (with the power off). Slide the nozzle and object together and if the nozzle gets further away from the object, manually twist the Z axis rods so there’s the same distance between the object and nozzle from one side of the bed to the other. That should get the gantry level enough that functioning Z motors should be able to lift/lower the gantry. Re-greasing with white lithium grease can help too.

If the gantry is level and greased, and the Z motors aren’t turning, it might be time to look at the Z stepper driver. If the stepper drivers are gone, it’ll probably be best to look at getting a new control board.

Rods move manually no problem. Leveled and tried to move via menu. Just buzzes. Doesn’t move. X and Y axis also not working. Movements via the menu also appears wonky. Value doesn’t always change when you rotate the knob. Is there any way to test the motherboard to confirm it is toast before ordering a new one? Thanks for the help!

It sounds pretty toasted. Buzzing is usually a burnt out stepper or driver.

If you have a spare stepper, ensure it’s wired up correctly and plug to the board and see if it moves.

I’d recommend either an SKR board or the Octopus 1.1… but that’s if you feel the whole machine is worth investing about $200 and a couple of hours to have it operating a little better than stock.