Intermittent Ready/Disconnected cycling on new OMTech 60W JPT MOPA (USBLMCV4, Board Signature 0000809802102402)

LightBurn Hardware Compatibility Galvo
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1

Hi everyone,

I’m hoping someone from the LightBurn team or anyone with a similar issue can help. I’ve spent the better part of two days troubleshooting this and have narrowed it down as much as I can.

Machine

  • OMTech 60W JPT MOPA Fiber Laser (Autofocus)
  • Purchased new approximately one week ago
  • Serial Number: 20260413027
  • Windows PC
  • LightBurn 2.1.03

Symptoms

The laser worked perfectly for approximately one week.

Beginning today, LightBurn has become intermittently unstable.

Typical behavior:

  • Connects normally
  • Frames normally
  • Successfully engraves multiple jobs
  • Then suddenly begins cycling:
    • Ready
    • Disconnected
    • Ready
    • Disconnected
  • Sometimes LightBurn freezes completely.
  • Sometimes it freezes when selecting PORT #1.
  • Sometimes it happens when clicking Frame.
  • Other times it happens when clicking Start after framing has already begun.

The behavior is intermittent.

For example, today I successfully engraved approximately 10 stainless steel trays over roughly two hours before the problem started again.

After restarting the laser, I was able to engrave one additional tray before the issue returned.

Error

Earlier in troubleshooting I also received:

Unrecognized board signature: 0000809802102402

I understand from reading the forum that this message by itself may simply indicate a newer controller revision. However, I don’t know whether it is related to the communication issues.

Things I’ve already tried

  • Two different USB printer cables
  • Direct USB connection to PC (no hub)
  • Clean reinstall of LightBurn
  • Fresh device setup
  • No imported device settings
  • Only imported a .clb Material Library (no preferences or device files)
  • Windows Device Manager consistently shows USBLMCV4
  • Device Manager reports:
    • “This device is working properly.”
  • Windows never appears to lose the USB device.

Additional observations

The machine itself appears capable of operating correctly.

The engravings are excellent when it works.

The disconnects are intermittent.

I have also noticed that the internal fans appear to change speed when the communication problem occurs, although I haven’t yet determined whether the controller itself is resetting.

The garage was quite hot today (approximately 97°F outside), so I can’t completely rule out temperature, but I’m not convinced that’s the root cause since the machine will sometimes reconnect after only one additional engraving.

Questions

  1. Has anyone seen this behavior with newer JCZ/LMCV4 controllers?
  2. Does board signature 0000809802102402 correspond to a newer controller revision?
  3. Is this a known issue in LightBurn 2.1.03?
  4. Are there any logs or diagnostics I can collect that would help narrow this down?

Any guidance would be greatly appreciated. At this point I’m trying to determine whether I’m dealing with a LightBurn communication issue, controller firmware issue, or a hardware problem before I pursue a warranty claim with OMTech.

Thank you.

2

The USB connection is managed by Windows, not Lightburn. Lightburn only uses it.

It appears you tries nearly everything usually proposed. Except:

  1. Have you tried using a different USB socket on the PC?
  2. Have you considered it might be a bad USB socket solder connection on the controller board? I had one fall off on my CNC machine. Have you contacted the manufacturer?
  3. If Windows does not drop the connection, then it has to be an electrical fault.
3

Hi Mike,

Thank you for the reply.

My computer has only USB 2.0 ports, and i have tried all of them. Still the same issue.

I am on hold with OMtech tech support. I agree that it is likely a fault in the hardware but before i start ripping into this thing i am going to see what their tech support has to say.

Appreciate the reply.

4

Hi Richard,

At first glance, it does sound like a temperature problem to me.

The status cycling between Ready and Disconnected indicates that the controller is resetting. The audible change in fanspeed supports this.

When this happens, did you try leaving the machine powered off for a few minutes, and then try again? (Cooling down might be difficult in such high temps. You can see if an external fan pointing at the box helps.)

Either way, I’d recommend disabling the powersave feature on Windows, as explained here

Capturing a Debug Log could provide helpful insights. This would also provide us with the necessary information to add this new board signature.

5

Congrats on all the things you’ve tried and the clean report.
One note: Reinstalling LightBurn very rarely solves any issues, because the settings remain untouched. Instead, you can restore all settings from an automatically generated Prefs Backup, if they changed in some unexpected way.

6

Hi Aaron,

Thank you for taking the time to look into this and for your suggestions.

I wanted to provide one additional piece of information that makes me think temperature may not be the root cause.

The issue has occurred both when the machine has been running for a while in a hot garage and first thing in the morning after sitting powered off overnight. This morning the garage temperature was only around 70°F, and the controller still failed to connect on the initial startup. I had to power-cycle the machine before it would connect.

The behavior has been very inconsistent. Sometimes it will complete 10 or more engravings without issue, and other times it disconnects after a single engraving or simply when I click Frame or Start.

I’ve also tested:

  • Multiple USB cables
  • Multiple USB 2.0 ports on the PC
  • Driver reinstall
  • LightBurn reinstall
  • EZCAD (which also has communication issues)

I’m currently working directly with OMTech support, and after reviewing my troubleshooting and test results, their technical team believes the controller motherboard may be faulty and has started the process of sending a replacement controller.

I appreciate your help and wanted to keep you updated in case this information is useful from the LightBurn side as well.

Thanks again,
Richard

7

Alarm bells are ringing

It’s good to hear that OmTech will send you a replacement controller. Based on your thorough analysis, that must be the cause.

Please keep us posted how it goes with the new board.

8

This is what caused mine to show similar issues. If I wiggle the usb cord it can fail. I can tell it’s the usb connector on the JCZ board.

:grinning_cat: