I think my tube is empty

I went to use my glow forge after a month of not using it due to my day job. I saw condensation inside the machine lid and water under the honeycomb bed, and thought that water had crept up the exhaust into the machine. After the exhaust apart, there is no moisture in the exhaust tube or where it connects to the body. The inside is covered in dirty condensation so I think the glow forge is totaled. I receive an amber light at every power on. After cleaning and inspecting the machine up and down, I’m fairly certain that the laser tube is empty! That would explain the standing liquid I saw. I’ve sometimes noticed small bubbles moving in the tube on start up but I see absolutely nothing now. I know the coolant is optically clear, but I think it’s just empty. I opened the reservoir and dipped some q-tips in to check the level and they came away wet. I’ve manually moved the gantry, aligned the print head with the camera, reseated the laser head, reset the glow forge (teal button setup) Any ideas?

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You are not the first owner to have condensation in the Glowforge if you don’t disconnect the vent when the machine is not in use. The moisture in your machine is almost certainly there because of the vent tube.

Drying out the machine will be step one, and that involves more than just wiping away the moisture and “mopping up”. You will need to thoroughly dry the machine before powering it on again. Some have suggested putting silicone gel crystals in the Glowforge to augment the drying process, but I don’t know if that helps or not.

Don’t turn your machine on again until you hear back from Support. Open the lid, remove the vent hose and do your best to dry the machine. Good luck.

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The machine is dry. There is no evidence of moisture in the exhaust tube or at the exhaust connections at the machine or the window vent. All the condensation occurred in the machine itself.

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Yup! I did that within week 1 of having mine :slight_smile:

My background is in electronics and so I might completely be wrong in my understanding of material science of this; but I believe the condensation would be more evident in the machine itself as opposed to the exhaust connections and vent because the machine is a better environment for the buildup of condensation.

As for the bubbles in the laser tube, you should only see that on first power up and you should not see them once the coolant has been fully cycled through the lines and tube.

@samus1976 so just to clarify, you do not leave the GF connected to the window vent when the GF fan is not running (i.e. the GF is powered off)?

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The yellow light is usually either a temperature issue, or something wrong with the connection to the head. Check to make sure your white cable hasn’t come loose, check the contacts between the head and the carriage plate, and make sure the other end of the cable is still plugged in good to the circuit board in the left side.


The system is self purging, and nary a bubble in mine for years. If you do see bubbles that suggests either a lower than normal level in the sump or a leak in the system.


Hello! @samus1976 I am so sorry to hear about the condensation problem you are running into with your Glowforge printer and will do my best to help resolve this issue.

Go ahead and try your best to remove any remaining condensation with a dry rag, that would be most helpful. If you could also send over a photo of the laser tube I can go ahead and confirm if there are any problems with the coolant.

I extracted the logs from your Glowforge to investigate, and it looks like the orange button is appearing because the Glowforge is having trouble communicating with the printer head. There are two key connections I’d like you to check for me.

Could you please do the following?

  1. Turn off your Glowforge.
  2. Holding only the finished black surfaces, grasp the printer head as shown. Pull gently up and back to disengage the magnets and remove the head.
  3. There is a small tab in the center of the wire ribbon. Push down fully on the tab to release it, and gently pull the wire ribbon plug from the printer head.
  4. Take a clear photo of the gold pins inside the printer head where you just unplugged the wire ribbon. It should look like this.
  5. Pick up the printer head and wire ribbon. Make sure the tab on the wire ribbon is facing up. Slide the ribbon back into the head until it clicks.
  6. As shown, lower the printer head over the metal plate so that it rests next to the two round posts. Then push it gently away from you – you’ll feel a “click” as magnets pull the printer head until it sits snugly atop the metal plate.
  7. Pull the laser arm all the way forward.
  8. Reach over the laser arm, and to the left of the inside of the unit and you’ll see this circuit board:
  9. Take a photo of the circuit board. If the cable I’ve indicated above with the red arrow appears to be loose, please reconnect it and try printing again. This cable should ‘click’ back into place.
  10. Turn your Glowforge back on.
  11. Send us the photos you took in step 4 and step 9.

Once you reply back with the photos I will be more than happy to assist you with the next steps. Thank you!

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I have performed the steps outlined. No connections seemed loose, but I disconnected both and reconnected. Upon startup, interior fan is running but gantry makes no attempt to move. Amber light shows a few seconds after startup.

Hi @samus1976. Thank you for getting back to us with those photos requested by Ray to address the yellow light issue occurring. I was able to review the recent log files along with the photos and see that your Glowforge is continuing to have trouble with the printer head communicating with the rest of the unit.

This is not an indicator of any tube or coolant issues, and to address this, can I have you try turning off your Glowforge, and try cleaning the circuit board located to the left of the laser arm with some compressed air and then re-seat the flat white cable highlighted below?

Once the cable is re-seated, go ahead and turn on your Glowforge and try a simple test print. If you run into any error messages, or the print fails. let us know any time it was run, and we can review the log files for any next steps. Thank you!

Cleaned area as best I could. The dust and debris has been glued in place after being wet, so it doesn’t shift with compressed air or vacuuming. Disconnected and reseated the cable, and tried again. No change in behavior. Internal fan on upon startup. No movement from gantry, amber light.

Hello @samus1976, Thank you so much for working with my colleague Brandon on this problem. At this point in the troubleshooting, we have all the information we need to move forward with the next steps.

I just wanted to confirm that you received my e-mail before I close this post. Thank you and I look forward to hearing back from you on e-mail :slightly_smiling_face:

Hi @samus1976. It’s been a while since Ray’s response in this thread and I haven’t been able to confirm that you received his follow up email yet. I wanted to reach out and check in to see if you have been able to check your inbox, but just in case, I have included the requests from his email here to help:

Could you please send me the following photos?

Assuming you’re using a smartphone, try these tips for great photos:

  • Use flash
  • Zoom in using the digital zoom
  • Hold the camera/phone far enough back to get good focus.

First, please turn off your Glowforge.

  1. Motor on the laser arm (and surrounding):


  2. Inside, left of machine:

  3. Inside, front left side - small green board​​

    Next, gently pull the laser arm all the way forward.

  4. Reach over the laser arm, and to the left of the inside of the unit and you’ll see the larger green circuit board:

  5. Left side of front door:

Once you reply back with those photos I can determine the next steps. Thank you!​

Hi @samus1976. It’s been a while since we’ve seen any activity here, so I’ll go and close this thread. Free to check your inbox and reply to Ray’s response via email with the reference Ticket #316614. If you’re not able to see the email he sent, please feel free to write us at support@glowforge.com and reference Ticket #316614. That will allow us to continue the discussion on there, and get this resolved soon. Thank you!