Lightburn/computer no longer finds laser

I purchased a 10-high 60 w laser. Replaced the board with a smoothie I purchased from Cohesion3d. I paid for a lightburn license. I swapped the boards & set up lightburn, the program found the laser without an issue. computer dinged when laser attached. Designed for a bit,

now no connection - waiting for connection appears under laser window.

I have:
Went to device tab, try to get lightburn to find program and reconnect
replaced the usb cord
turned off laser, restarted computer and then turned on laser (and other combinations).
computer no longer dings when laser gets connected with usb (with old and new cord)
went to settings and unchecked box about power save and usb ports.
No joy

out of Ideas, very frustrated - really hope its something obvious and I am foolish.

You might have to select the proper usb port. On my linux machine, it will change the usb port when it reboots.


Alas, this was not a solution

A post was split to a new topic: JPT 50W connection / drivers

Without powering up the laser, connect with just the USB and see if LightBurn will connect and talk with the C3D controller.

You should have a Smoothieware profile selected in the Laser window in LightBurn. I believe that the USB power should be enough to wake it up and start talking to it.

Good morning;
Unfortunately, no joy. The computer does not even recognize that something has been plugged in. It “dings” anytime a device is plugged in. I know the computers USB’s work. Is it possible the USB on the card is just bad? When I plug the card in there are a lot of sparks (sophomoric to mention but I am trying to paint a complete picture) is it possible it shorted the USB?

The first pic (3236) is what happens when I open lightburn after plugging in the usb cord as directed, the second selecting the machine, third is after selection.

There should be no visible ‘voltage exchange’ when you plug it in.

If it’s actually ‘sparking’ then you have probably lost some hardware.

Some Chinese machines have issue with grounds or common mains connections.

One of my power supplies had about 50 volts on it’s ground when it ran… I tossed it but it’s not uncommon if you pick up low cost Chinese supplies.

Good luck


Thanks Jack. The power supply is the one that was supplied by the company that sold the card, so I suppose I can reach out to them.

If you own a voltmeter, just measure the difference between the outer shield and the shield around the receptacle or some other ground on the machine.

If you have more than one supply in the machine, it may be the other one…

I check every power supply I purchase from China this way. Already smoked one board…

Effectively the ground difference… It should be 0.


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USB ports on computers often have short circuit protection built in to protect the computer.

Does the USB spark without the laser powered?

The supply I purchased, had a 50 volt potential on the ground side. I fried a board when I tried to use it. If my pc had been plugged in it probably would be history.

The protection is for the supply and the data lines. Doesn’t cover virtually plugging it in the mains like this supply did…

My pc’s are desktops and plug into the mains with a common.


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