Glowforge Basic not centering

Hi! My Glowforge basic was working just fine and just finished a print. The solid amber LED came on when I sent another print with the error, “Head not found”. I powered the laser off , confirmed the gantry and head moved freely. I powered it back on and when the gantry moved, it moved slowly and the head did not move towards center. When the gantry stopped, the head moved towards center a few a couple of inches, stopped, moved a little more, stopped until it reached the center, then hung at centering before getting the amber led again. I powered it off, cleaned everything, reseated the ribbon cables and tired again, same result. I powered it off and moved the gantry and head to the center of the bed and powered the laser on. It seemed to center but when the gantry moved back to home, it moved maybe 2 inches, made a bump sound and all motion stopped. The amber LED came back on. I confirmed that nothing was in the gantry or heads path and no unusual sounds were heard when I moved everything. Could I have a bad stepper motor?

Most likely the cable that connects the head to the rest of the laser has come loose or been damaged. With everything off, disconnect the cable and make sure that the tiny gold pins are all there, centered, and bounce back when you push them. If that’s a yes - plug your cable back in, push everything to the back/left, and start it up again.

Fingers crossed!

Welcome to the community, there’s so much good info here :slight_smile:

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Hi Deirdrebeth,

Thanks! I’ll check that cable. Hopefully that’s it.

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Ok, so update. I reseated the ribbon cable and what I see is happening. When the gantry moves to the centering position, the printhead is not moving towards the center at the same time, and a quick grinding sound can be heard. After the gantry stops in the center, the printhead will move a couple of inches towards the center, pause 15 seconds, move another couple of inches, pause 15 secs,…etc. until it reached the center. It will go through the centering motions the 1 of 2 things will happen.

  1. The printhead will move the right along with the gantry for 1 second before a loud bump is heard and the amber led lights.

  2. The printhead will move back to home with the gantry, but the printhead movement is erratic. When a print is sent, the laser will start to print but the printhead movement will be so erratic that the print fails after a few seconds.

Would the ribbon cable cause this or would this be the stepper motor that drives the prinhead?

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That definitely sounds like a lost connection - it makes that noise when it’s lost and the stepper doesn’t know where to go, plus that matches with the error you got.

Check along the length of the cable, sometimes they rub and end up with a break in the plastic. If you find something like that try covering it with tape.

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I didn’t see any breaks in the cable, but I’m going to try replacing it and hopefully that will fix the issue.

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Any breaks in the cable can easily be invisible and even episodic as the break occasionally touches. However, if you make sure the machine is off and move the head directly under the camera and turn the machine on. If there are other problems they will show up, but finding the head will not be one of them.

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