Carriage and head keep crashing into upper left home position

Tonight I turned on the machine and the carriage/head thumped against the limit stops. It was turned off with normal behavior yesterday with the carriage/head parked at home.

Every 10 sec the system tries to move again, each time with the white light button flashing. After 5 or 6 of these cycles. I turned power off and then back on. Same thing.

Then with power off, I moved the carriage to about center of the bed and the head to about center also. Power on. With 10 sec between attempts, the head moves 1/2" to left, pause 10 sec, then carriage moves back 1/4". After several cycles, I turned power off.

What to do?

Please help.

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It uses the camera mounted under the lid for calibration when booted up so maybe the lens needs to be cleaned.

Try placing a piece of material on top of the lid. I havent had this issue in a quite a while but it seemed like either bright light or just intense/glaring spot light caused issues with calibration happening. A piece of cardboard or other material on top of the unit to block the light could remedy it.

Currently I’m noticing mine will not calibrate if there is material inside the unit at boot-up, so if you have anything in there, pull it out.


Magic! Took out the PG board, put cardboard on top of closed cover and powered on.
Everything proceeded normally.
I had cleaned the camera lens two days ago and normally do have material in the bed when powering up.

Thank you for getting the machine going!


During calibration at startup the server looks for the head. It will send instructions to move the head a specified amount based on where it thinks it is, and the camera images the bed and sends that information by wifi to the server. the server will respond with further instructions and the head will move again, and send another image to the server. That’s the reason for the pause, the communication back and forth. it’s also the reason a solid WIFI connection is required.

The dance should result in the head under the camera where the server sees the glowforge logo directly underneath the camera, and will travel to the left limit and jocky the gantry a bit and park the head in the upper left corner. That’s when the server is satisfied it knows where the head is, and considers itself synced with the machine. Calibrated.

Just let it finish its dance and you will be good to go. I took a sharpie and indexed where the gantry should be and where the head should be when it is directly under the camera. Before I turn it on, I position the head there so the server sees it and doesn’t need to search for it. Might only save a couple of seconds, but the server never has to play hide and seek.
It is normal for the button to light up when the machine is exicuting instruction.


After 6 cycles of trying to move past the limit stops, the machine seemed to be in an endless loop. First time that has happened.
Good to know more details of what is supposed to happen.

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Thanks for the help @PrintToLaser and @mpipes!

@brok09 I’m glad you were able to sort things out. Since you’re back up and printing, I’m going to close this thread. If you have any other questions, go ahead and post a new topic.