Head hits left side in startup + LED strip out

Hello Glowforge team,

I’ve run into a pair of the problems seen elsewhere on this board:

  1. Every time I start the Glowforge when the head is parked in the top left corner, it crashes into the left wall. I can hear the stepper motors fight for a half-second, but the app reports “obstruction” quite quickly and does not try again. Each time before powering on I have to manually (and gently) reposition the head to the center of the bed so the camera can detect the Glowforge logo. Once that happens, the head speedily moves to the left wall and stops where it should, then speedily moves to the back of the machine and parks where it should, and everything’s good from there. That said, the Glowforge doesn’t seem to remember or detect where the head is: after power cycling it will bump the left wall if I don’t recenter the head, and that seems to be the case across several restarts.

  2. The right LED strip on the lid seems to be out entirely. This makes the camera images quite dark, though the bed image does properly update in the app.

I’ve done a cursory check of the ribbon cable (intact as far as I can see) and five expected connectors (all flat, clamped, and looking good). The LED strip power connectors at the outside corners of the lid also appear to be connected and intact.

Could this be a bad ribbon cable? Are there any other diagnostics or tricks I can try, like using a multimeter to see if the LED strip is getting any voltage?


Wiggle it, just a little bit?

Which? The ribbon cable connector, LED power, or head?

Not the head, but any place where there’s a connection on the way to the LED strip. Just to see if anything is loose or broken.

It’s possible that the lack of light is why the camera doesn’t see the head properly when it’s in the corner.

I have found it best to always leave the head to the back left (put there as needed with the machine off).

The only time I had problems with it bumping into stuff was when I started with it someplace else.

I’m sorry that your unit is having trouble centering the head when you turn it on. I extracted the logs from your Glowforge, and the behavior you’re seeing at start up might be related to the cameras images being too dark for the unit to center the head correctly. This would be consistent with one of your LED strips being out as you’ve described.

If all of your lid cable’s connections and connections to the LED strip are normal, it’s likely there’s a problem with your black lid cable. Will you please let us know what you found after checking the cables like @chris1 described?

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No offense to your problem though @jeffbowman. Support will set you straight.


I can confirm that the ribbon cable (back of unit, back right of lid, front power conneectors) all seem quite solid. I held off from actually disconnecting and reconnecting them just to ensure that I didn’t damage anything for lack of instruction.

I appreciate the humor of “wiggle it” but am unfortunately under a bit of time pressure, and have just seen the unit bump the left wall even when starting centered under the camera. I’m hoping that our attempts to cut won’t cause the Glowforge to damage itself.

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Thank you for checking your cable connections as well as for the detailed photos. Since everything looks like it’s connected normally, it’s likely that the black cable on the lid has a problem. I’d like to send you a replacement for that cable, along with some instructions on how to replace it so we can get you back to printing as quickly as possible.

I’m going to close this thread and I’ll be in touch very soon via email to sort out the details of getting the replacement cable sent to you.