Y-axis not responding

Initial problem was media not sticking to table, but table had a huge bubble, so replaced heater with new steel plated heating element and replaced glass plate, supports and washers. Now during start-up the table (y-axis) moves all the way forward and never moves again. I can still move the x and z axis but not the y. Any ideas?

Specifically, which printer model do you own?

This can happen if the end-stop (switch) is disconnected or the wire is damaged.

Lulzbot Mini (not the 2). Before I start it each time I move the table by hand to the middle position then start the program. Each time it’s started the table moves all the way forward until you hear the limit switch click, it moves back about a half inch then forward again to the stop and then never moves again. It will continue with it’s start up and the cleaning swipes are done with the cleaning pad about an inch in front of the injection head, then it fails when trying to locate the first corner because the corner isn’t there because the table never moved.

I don’t have a Mini 1 … on my printers the limit switch on the axes are wired “normally closed”. When the printer hits the limit switch, the button breaks the connection (it changes to “open”) and this interrupts the signal.

But what this really means… is if you have a damaged or disconnected wire (no continuity flowing through) the printer will interpret this to mean that the printer has hit the limit switch. It will refuse to move farther in that direction.

You can open your control box (careful when you open it to not yank or strain any wires as you pull open the case), find the wires for the Y-axis switch (I think there’s a Y-max and Y-min but probably only one is wired… it isn’t really necessary to wire both) and use a multi-meter to test if the wire has continuity.

Thanks, did as you suggested and both limit switches appear to be normally open and both are working correctly. I went one step further and made a block to trick the Y+ limit switch to stop the bed in the correct position for the head to line up with the cleaning pad and restarted. The bed moved forward until the limit switch hit the block and stopped, then the head came down and wiped back and forth then went to check the four corners. The bed never moved back so the alignments were all done on the corners on either side of the cleaning pad. So the Y-axis control motor works and the limit switches work but there is no Y-axis control.

You can play some games such as swapping the X & Y axis limit switch wires or swapping the X & Y axis motor control wires … and see if the problem follows the motor … or follows the board.

This is a way to work out if it’s a wire issue, a switch issue, a motor issue, or a board issue. (of course you can’t leave them in a reversed state … but it is a quick way to help isolate the issue.)