RedSail M900 Laserboard conversion

Machine: RedSail M900 with Leetro MPC6515

Board: C3D Laserboard (waiting to be shipped)

Firmware: Planning on using Smoothie Gcode firmware

Problem/ Question: So I got a RedSail M900 lasercutter wich was left somewhere for years. I’m planning on reviving it with a LaserBoard.

I don’t know if the M900 fits in the description of a K40 laser.

I ordered the Laserboard with the stepperdriver cables, so i can use the original stepperdrivers in the M900.
Then i started reading the K40 upgrade guide, but i’m doubting if mine is a K40. The guide says it comes with a K40 Laser-Specific configuration file. Does that configuration also apply for my laser, or what do i need to tweak in the config file to make it work?

See pictures attached of the board and a quick picture of the stepperdrivers


That’s definitely not a K40 :slight_smile:

You should follow the instructions in #documentation on how to connect the LaserBoard to external drivers with the signal cables you mentioned.

You will definitely need to change the configuration on the board’s memory card for your machine. There are a number of other “large machine” conversions with different controllers though, I would recommend skimming those threads.

This is the most recent one. It has a bunch of unrelated stuff being talked about also:

Thanks, i already found the documentation on connecting the external steppers. Just recieved the shipping conformation. Can’t wait to have the board installed. Keep you posted!


Picked up the board at the post office today, will try after this weekend. Keep you posted

So i tried to document how the existing board is connected before taking it apart. Then i started to connect the stepperdrivers first to see if they are moving with the LaserBoard. Thats where i discovered the first challenge. The image at the documentation pages says it has Pul+/- Dir+/- and EN+/-. The pul and dir are on my stepperdrivers but the last 2 connections are named OUT +/-.

What does this mean, is it the same and can i connect the black/red wire to them?

See photos attached

It’s likely you’ll want to leave the OUT lines disconnected. These are used for the driver itself to power some sort of programmable logic controller that you likely won’t be using. If they were previously connected, please show pictures of what it was connected to and how.

They were not connected. So i’ll better leave them disconnected then.

See the empty terminals on the right.

Excellent - yeah leave the OUT lines disconnected and the red and black wires will go to the EN+/EN terminals (respectively) - the rest looks properly connected.


Make sure each wire (color) is connected to the proper position name as per our diagram there. PUL means the same thing as STEP on your driver.

I think all the wires made me blind yesterday. Didn’t see the EN terminals before the OUT terminals… So I thought there was no EN on these steppers.

Never mind this question…

Gonna try this later today. Then i will be back for info about connecting the laser PSU.


Allright! Stepperdrivers are working, can move the axis from lightburn. The endstops are top right and just switching contacts. Ordered the molex connectors to connect them to the LaserBoard.

Last thing to do is the laser powersupply. Did read a lot about it on the forum but never found the exact explanation of the connectors. Most machines are just with a white connector you have to put on the connector on the board.

Is the Laser Fire output on de LaserBoard the PWM output?

So this what i found myself for connecting the LPS:

This is what the original scheme was

I made a schematic of how it was connected to the old board and i added some pictures of the powersupply.

See if this helps:

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