Benbox controlboard

I bought a secondhand laser machine with a broken laser and a Benbox control board. I have another 15W laser laying around so I hooked it up with LB and it connects. I can ask for a $$ and see the list of values. The stepper motors work. I don’t know how to set this machine up. The GRBL values don’t seem to be the same as the “normal” GRBL value, at least they don’t react the same.

Should (or do I need to) update the firmware to make it work with LB? What settings do I use? When LB scans for a laser, it can’t find anything.

I would appreciate it if someone can point me in the right direction to get this up and running. Thanks in advance!

Scherm­afbeelding 2023-08-01 om 18.01.39

EDIT: is it a matter of flashing the arduino to GRBL1.1 or is there more to it?

If your controller has an Early GRBL and the Machine Settings aren’t offering $32 as an available setting, reflashing to enable Laser Mode is probably worthwhile.

In the Console window in LightBurn request the following reports:
pressing Enter after each one. Please copy and paste those reports into a reply here. I’d like to see what you’re working on.

Which GRBL do you have on this controller?

What’s the number on the processor of the small Arduino board?

I’ve flashed one. It wasn’t too bad but it may not be necessary here.

Thanks for your help John, I appreciate it!

This is what Iḿ getting when I connect:

Grbl 0.9j [‘$’ for help]
Your Grbl may not support Variable Power mode (M4)
If your laser does not turn off between cuts,
switch to the GRBL-M3 device

The other reports:


$0=10 (step pulse, usec)
$1=25 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=7 (dir port invert mask:00000111)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=3 (status report mask:00000011)
$11=0.010 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=0 (hard limits, bool)
$22=0 (homing cycle, bool)
$23=0 (homing dir invert mask:00000000)
$24=25.000 (homing feed, mm/min)
$25=500.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=1.000 (homing pull-off, mm)
$100=400.000 (x, step/mm)
$101=400.000 (y, step/mm)
$102=400.000 (z, step/mm)
$110=500.000 (x max rate, mm/min)
$111=500.000 (y max rate, mm/min)
$112=1500.000 (z max rate, mm/min)
$120=10.000 (x accel, mm/sec^2)
$121=10.000 (y accel, mm/sec^2)
$122=10.000 (z accel, mm/sec^2)
$130=200.000 (x max travel, mm)
$131=200.000 (y max travel, mm)
$132=200.000 (z max travel, mm)



I see that the nano on the controlboard is a clone, I have tried flashing it but that didn’t work unfortunately. I tried that with the Arduino IDE and with the Xloader. Both times no error messages but also no good result…

It looks like 0.9

This is the chip on the clone Arduino:

If worse comes to worse, would a new arduino nano work on the board? Would that be better?

The CH340 Chip is the communication chip.
the square processor chip may be on the other side.

It appears that the Nano can be either an Atmega168 or an Atmega328p
Please confirm. If it’s an Atmega328p then it’s mostly a known factor.

It would be prudent to map the data pins from the arduino to the inputs and outputs.

Stepper Drivers. Is the driver chip marked 4988?
Clock will be the same on all 3. one pin on the arduino board.
Some of the Driver behavior settings will be hardwired on or off.
Each driver has a pin for ‘Active’ and ‘Direction’. Those should trace directly to the arduino chip. The outputs go to the nearby motor connector.

Stepper Clock:
Active X:
Direction X:
Active Y1:
Direction Y1:
Active Z:
Direction Z1:

I would most likely select the three pin connector next to X-Axis for modern laser module control. You’d need to know which pin that TTL PWM pin connects to. 24V Power and Ground are hardwired.

Laser PWM pin:

After that the 7 pins on the Limit Switch Header. I can’t read them from the photo. Please check if they all attach to ground or +5V or some of each (on the back of the board).

It would be good to get the Label on the Benbox board and the data pin, bonus points if they all connect to +5v or ground.

  1. Label: Data pin: Ground or +5V (for all 7)

Now all that’s left is optional stuff.

The Spindle Motor plug should trace back to the big upright transistor, if it’s 3 pins, one of the pins should be a data pin back to the arduino.

Spindle Motor :

The three other sockets below the spindle motor appear to offer PWM power (2 pin control) each of them would have one pin from it’s adjacent power transistor to the Arduino.

connector 1

connector 2

connector 3

It may be of interest to explore the three pin and 4 pin headers top RIght.

From that the GRBL 1.1f or 1.1h could be configured to enable homing, comntrol the stepper drivers and select the variable power Laser pin.

If you have the smaller processor on the Arduino Nano then it’s probably worthwhile if the pins are all the same on the Nano board.

Yes, it is a Atmega328P

Unfortunately, I see no markings or numbers on the driver chips:

The laser works with the 3pin connector and the steppermotors also work. The amount of travel is the problem (what normally is the $100 and $101 settings are)

They all connect to GND on one side, the second pins all trace back to the arduino


These are labeled:

  1. Air-cooled (12v)
  2. Water-cooled
  3. Laser tube (12v)

I found this online, this looks almost the same as the board that I have:

It would be great to get this one working with GRBL1.1, having said that, when it requires too much work, it might be easier to replace the Arduino nano (if that would do the job) or even the total board. Obviously, I’m not as technical as you seem to be, so I was looking at the possibility of an easy fix. As much as I appreciate your input and advice, for me the main questions is:

Would a new Arduino Nano with GRBL 1.1 work on this board you think? Or would you advise just to replace the whole board? Fixing this one would be great, when it’s too much hassle, I can get an affordable Makerbase DLC32 online when that might be better…

Thanks again John! Appreciate your help!

That’s news to me… I thought they were all 328p… I don’t know how you could shoehorn grbl in one

Processor Ram Flash EEPROM
328 2k 32k 1k
168 1k 16k 512B

I didn’t know there were variants…

It’s the large chip on the usb board…


This is the schematic… I use… 328p…


That’s a standard nano, like mine…

This link shows how to upgrade using benbox… Video is 4 years old but should work… You should find firmware over the 1.0 version… usually something like 1.0F or H…

Good luck


Wow, I think it worked, I have version 1.1h now on the Arduino. Time to reconnect the wires and test it! Thanks!

Grbl 1.1h [‘$’ for help]


Target buffer size found

The only question that remains is, what is D11? Could that be the PWM/TTL pin?

Scherm­afbeelding 2023-08-02 om 18.10.56

The silkscreen says this goes to the laser module… so the left pin must be pwm… There are two D11, suspect they are just different connectors for the same signal.


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It works but not right again. I’m used to working with a CNC and I thought that GRBL was universal. With my CNC it’s easy to change the distance of travel for my axis. ($100/101/102) When I change my X value because the distance it travels is far too big, it does affect the distance somehow but not nearly enough. Also, sometimes the speed of travel changes with the $100 value. So is there still an issue with my controller board or am I missing something here?

You can derive the values for $100-102 mathematically.

Create a design 100x100 mm and burn it. Measure the actual burn. Then change values of $100-102 in proportion to the difference in measurement between the design size and actual size.

If this doesn’t make sense provide the measurements for the burn and the current values of $100-102.

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Thanks! I’ve got the $100=45 right now, that’s about right. Is that normal when it is this low?

There is no normal. It’s entirely dependent on your stepper driver, motor, and gearing situation.

True, I should have said “unusual” maybe. But you’re right, as long as it works…

Will do that, thanks!

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