How to wire new display into K40

I have that same version of the machine, but I want to completely replace the control panel. I’ve purchased a potentiometer and a digital display, as well as an analog mA meter. I know how to wire in the mA meter, but I don’t know what wires to use from the crappy digital push button thing, to wire in the potentiometer and digital display.

Can anyone help me with that?

Thank you in advance.

I’m running Cohesion 3d Board. Upgraded Z Axis bed. Upgraded lights. Air assist. Mirrors and lens, laser head, visible laser and camera.

The potentiometer needs to be connected to the LPS pins GND, IN, 5V (the IN pin in the middle of the pot). Those pins need to be disconnected from the digital control panel.

If by “digital display” you mean a led voltmeter, you might connect this to GND and IN to show the voltage of the power set with the pot, but I would not connect that, because the value will show 0-5V and is not realy telling anyhting. The tube current is eveything. Don’t go higher than 16mA or so (or your tube will degrade quickly).

If by “digital display” you mead the GLCD, there is a special connector for this on the C3D board.

See the folowing topic for the digital to analog convertion:


@cprezzi I add the voltmeter to the IN so that I could repeat a specific pot position setting for a job.
When I run a job I write down the voltage reading in the job parameters. When I rerun that job I set the pot to that value.
The voltage value is really a pot position indicator that I can set without having to fire the laser.
I also use this reading to note when the relationship between the LPS voltage vs current has changed. i.e. tube or LPS wearing.


This is what I was looking for. I’m just a tinkerer, so I don’t know much about electrical circuits and such, but I was able to find a diagram somewhere and with your explanation, it makes sense now.

Thank you very much.