Would like to upgrade CMA-535

There’s a lot going on there with that driver board. This photo brings up some questions about where things are connected and how.

I’m guessing the 6-pin connector at the bottom-left with red/yellow wires is the driver power supply. The connectors labeled X / Y at the bottom clearly correspond to the connections Ray asked about so are almost certainly the drive logic.

From your description it looks like you’ve narrowed down where the various motors are connected and that weird block of ceramic wirewound resistors.

With some careful testing and futzing around, I bet that particular stepper driver could be used with the Laserboard. But, if this were my build, I’d gut it and replace it with some modern digital drives.

I find it odd that X has the larger NEMA23 and Y has the NEMA17. Normally you’d see the reverse. Does the gantry beam move in the X direction (left-to-right) on this particular machine? (There weren’t any pictures of the motion control).

The Y motor can be driven directly from the laserboard’s built-in drivers with a current of 1.0A. The X motor has a current requirement of 4.2A and will require an off-board driver no matter what. Even the standalone driver Ray sells may be a bit anemic for this purpose. I’d recommend a Leadshine DM556 to go with this motor. Wire the coils in series.

Loather thanks for your response. Definitely a lot going on for what its doing. I am starting to think the same… gut it and update.

You are correct the red/yellow wires are power in 36vdc. The bundle of yellow from the two 4 pin connectors head over to the resistor board. The others have been described above.

I miss spoke earlier the Y is the NEMA23 and the X has the NEMA17. I was thinking about its physical location not the translation direction.

So with the change of plans, would you recommend swapping out the NEMA17 for a 23? It grunts and groans if I move the X in a higher velocity. Upgrading the driver boards to something a little more robust such as your recommendation. Possibly upgrade power supply for the driver boards.

Thank you again.

Hello all,
I’ve been slooooowly rebuilding the CMA-535. Update on progress, I’ve gutted the entire system of all OEM control parts. I have upgraded steppers motors, stepper drivers, added some new user interface controls. Please see photos.

I have reached a point where I need to connect the LPSU to the control board along with limit switches. I have a few questions:

  1. Previous communications talked about connecting “TTL” or “TL/TH” What is this? I have searched the forum for a description or how this would be used with no luck. I would like to understand where the Yellow wire (Laser power control signal) Green wire (Laser switch control +) and Black wire (LGND) gets connected too. There is a Red (power of laser power supply) I feel this will not be used.

  2. The laser board limit switches have Sig, Gnd and V+. The switches I have are just switches… open or closed, can I just use the V+ on one leg of the switch and connect the the other leg to Sig??? ls it that simple?
    Thank you

Sometimes I want to write a documentation article in response to a support inquiry, and then that takes a lot longer than expected and I disappear for a month. I’m going to try not to do that, and actually respond directly :slight_smile:

On a typical CO2 laser, TL and TH are inputs on the LPSU that tell it to fire the laser. TL is a low = on signal and TH is a high = on signal. Only one of these should be wired on the LPSU.

Please consult these resources:

Remember, we are not in front of your laser and wire colors don’t mean much, but pin numbers/ names do. Isaac gave you good info to work off of in a previous post:

I can clarify some of those things but the fundamentals are good.

IN on the LPSU is a separate input, that in the case of the K40 is where a potentiometer goes (between GND, IN, and 5V on the LPSU) to set the max power, and then the LaserBoard sends PWM pulses to TL to fire the laser.

Your machine is quite different, as I did not see an LPSU that matches anything that we recognize.
Read those 2 links above and then reply back so we can get into the more specific details of how to do yours.

A simple switch should be connected to the SIG and GND pins of the endstop headers.

You should also find this helpful:

Ray, thank you for the information. I was able to get the limit switches wired in and functioning through smoothie. I was also successful with adjusted the steps for proper cross head movement distances.

All that’s left is the LPSU…

I have found a link
This is the exact model I have.
Could you suggest the best way to wire the LPSU to the laser board.
Thank you for all the help.

Ok, cool, so there is a distinct LPSU, good. HY- model # is something we are familiar with, it just seems like this model has the DB connector instead of screw terminals. Ok.

I gave you resources above in my previous post. The way most consistent with how everything is done now is to wire a pot between Gnd, IN, and 5v - although they make references to IN only wanting a max of 3.3v? which I have not seen before. I think you can just start off your pot really low and use a multi meter in voltage measurement mode between the GND and IN legs of the potentiometer, you can see what voltage is coming across them.

Then touch TL to Gnd and see if the laser fires and what the mA gauge reads. No mA Meter? Now is a great time to add one.

Tune accordingly to figure out your maximum laser power level and set the pot to 80% of that.

Finally we will connect TL and GND to the LaserBoard “Laser GND” and “Laser Fire” outputs as covered above above.

Ok, so I have hooked up a 10Kohm pot. GND, IN, (yellow, laser power control wire) 5v. I have this connected to a standalone 5vdc power supply. I then set the voltage lower than 3.3v. I have the GND of the power supply connected to the LGND. When I touch the LGND and TL wires together the laser did NOT fire. The laser WILL fire when test button is pressed.

I did ohm out the DB connector the only pin that did not correspond to the manufacturing schematic is pin 9. I did refer back to the schmatic i received from the original suppler of the laser. Pin 9 of the DB connector is 5v power from transformer then jumpered to L5V , 5v1K pullupward. I would assume 5v1K upward is referring to 1kOhm resister? Do you think this needs to be connected to something?


I did take the opportunity during the up grade to install a mA meter to monitor the laser power.

Thank you

You would not do that, you would connect that leg of the pot to the 5v coming from the LPSU.

Okay that make sense… However I don’t have a 5v coming from the LPSU. That’s why i hooked up a separate power supply. I do have 12v coming from the LPSU.
Do you think the original setup used the 12v through the resisters to knock it down to 5v or 3.3v?

The pin out sheet says pin 35 was 5v transformation.

The pinout above says Pin 3 on the DB9 connector is 5V out.

The original manufacturers spec sheet says pin is populated. The schematic I received from Jameson’s laser indicates no wire I connected to pin 3. I have confirmed the DB connector is pinned to Jameson’s schematic.
There is no wire connected to pin 3 internally of the LPSU either. Makes me think this LPSU was modified by Jameson’s laser.

What’s your thoughts on using a voltage regulator?

Ok, you’ll have to play with this a little bit to figure out how to fire the laser. I’d recommend removing the pot from the equation for now.

If you can touch 2 wires together and get the laser to fire, we can work with that. You may want a 220ohm resistor in between said wires to be safe, as they suggest.

Wrong rabbit hole to go down.

Readjusting plan to use alternate method of laser control.

Also, proprietary stuff is great.

Because I have to: https://xkcd.com/927/

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Ok, I was able to get the laser to fire…

This was the process:

After studying and doing some deep understanding of what the laser spec sheet is really saying. i concluded the following.

(Green Pin 6) description reads “Switch Light Control, internal through 200 resistance pull up to 5V, when TL connect to the ground HV output, when unconnected there is no HV output” I take this as a safety circuit, it needs a ground to control HV output. This could be tied to a lid switch or some other safety circuit. I started by connecting LGND (Black pin 5) and TL (Green pin 6) together.

Then I took the (Red pin 8) output power 5v, (This is actually 12v), I connected this to load side of the pot. Then connected the ground to the pot (Black pin 5 and Green pin 6)

Backed the voltage down to 3v.

I then touched the (Blue, I HAVE NO CLUE WHAT THIS WIRE DOES pin 9) to the 3v from the pot and the LASER FIRED!!! Finally something!!

I connected the (Yellow pin 4) to the output of the pot, with this connection I was able to control the mA output, when the test button is pressed. I have the output set to ~20mA.

So with the success of laser firing when (Blue pin 9) is powered. I connected this to the Laser board fire and the grounds to the Laser board GND. Started Lightburn power @ 100% speed a 10 mm/sec for a test cut…fingers crossed. Nothing… no laser.

I metered the output from laser board as Lightburn was running the test cut. laser board GND to Laser Fire, I get a negative voltage. -1.5v to -0.05v. Is this suppose to be positive?? I think the laser would fire if the power was positive. Thoughts???


Bueller…Bueller? Anyone out there???

I’m going to focus on this for a moment. If your laser is firing from a positive voltage signal, then that is what we need to give it. The Laser Fire and Laser Gnd outputs from LaserBoard are a “connect this pin to ground” so 0v and negative voltages. What you need is the “Alternate PWM Out” header which provides the laser fire signal level shifted to positive 5v.

So that header (2 pins, directly between endstops row and the large white plug on the board).

5v, possibly run that through the pot so that max out of the pot ends up being 3v or whatever.
Ground. This is actual board ground and not an isolated thing so be careful.

BOOM! Works like a charm.

Thank you all for the great help!

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I know I’m trying to bring a 2020 thread back to life, sorry about this.
I manage to get most of the stuff working, but I’m still working on those YELLOW and BLUE wires.

After I grounded the green wire (safety),
then connect the yellow wire to the 3V output of the pot,

touching the blue to the ground or +3 or +5 does nothing.
If I touch the blue to the ALT_PWM 5V (or even the - pin!) of the Cohesion, the laser fires.

However, that ALT_PWM+ shows 0V to the ground using a volmeter.

I tried connecting the black wire to the ALT_PWN- then the blue to the ALT_PWN+ and still the same, the laser fires immediately.

Your thoughts ?

Any suggestion on how to connect those yellow and blue wires !?
@Cohesion3D Suggested to connect the Blue to the output of the pot (pot feed by the ALT_PWN) but then where do I connect the yellow wire, who is supposed to supply the input PWN signal according to the CMA documentation ?

Cancel that !

When I tied both ground from the laser, to machine ground as well as C3d PWN NEG together, the problem went away.

So, for the next reader looking for a solution for his CMA-1200 or CMA-535:

1- All grounds tied together (the machine ground from the laser, the signal ground from the laser, the metal ground of the machine, and the - on the alt PWN header.

2- The pot is fed with the 12V from the laser (black and red).
3- The output of the pot, once ajusted to 3V, is connected to the YELLOW laser wire.
4- The BLUE laser wire is then connected to the ALT-PWN + wire.

That did it for me !
Now I “only” have to solve my limit switch problems.