Taz 6 Homing Issue

I have had a refurbished Lulzbot Taz 6 from Matterhackers for around a year and a half and have never had any issues until the last couple weeks. As of lately, it refuses to home. I have made sure that the frame is squared, x-axis leveled, cleaned everything with alcohol and a scotch brite pad (pads and hotend). Everything is spotless and should be making good connections. It still refuses to work.

I have taken the bed off and put it back on. The printer is on a completely flat surface. I have ran the test command M420 S0, G28, G29 V4 before in the past to make sure that the corners are within range of each other, which they are. For the last couple weeks, when I try to run that command it just push down into a corner when it gets there.

So than I thought that it could be a bad hotend connection issue. While I got a new hotend, I also did an Archim 2 upgrade thinking that one of those would solve the issue. Sadly it still will not home.

Like before, it will home the x / y / z and but than will go to the first point and push down into the bed. It will go as far as to bend the bed a bit. To see if it was just a corner issue, I made another corner the home and it does the exact same thing. This makes me think that it is a physical bed issue since the same problem happens with a brand new board and hotend while everything is spotless and should be making a great connection.

Any ideas ?

Check the continuity between the nozzle and the washer with an ohm meter, sounds to me that you have an open circuit and that’s why the nozzle keeps pushing down on the bed/washer.

If the continuity check is good, heat the nozzle to a temperature 5-10 degrees higher than you normally use and then clean it with a scotch brite pad or turn off the power and clean it with a brass wire brush.

Sometimes there’s a thin film of filament on the tip of the nozzle and this should remove it.

I’m having the same issue.

Turned out the bed connector was bad. The little bullet connector had backed itself out just a hair. I had to redo the connection and it all works now. It was the stock 4x4 connector that only has a red and a black wire going to it

Ok thanks for the info. I will take a look and see if I have the same issue

I’ve seen this happen as well; I’ve found that cleaning the nozzle is the quickest solution, and something I should probably do anyway. Apparently extra plastic stuck onto the extruder prevents electrical contact needed for homing; the software keeps trying to jam the extruder down further an further.
Use a non-conductive pad like Scotch-Brite.