My engraver has once again started banging against the rail

I use lilghtburn and have Ruida controller. Replaced x prox senser for second time. Now it won’t recognize y position. Have replaced both mother board and controller. Nothing works. It worked for a while this week then just took off in a strange direction and hasn’t work again correctly. I’m ready to toss the whole business. Y sensor lights when i place a screwdriver over it and the light on the mother board lights as does the x sensor. It will not home or move smoothly on the y axis.
This is very strange. Please help.

Have you checked to see all your mechanical parts are running smoothly on that axis? Make sure everything is not too tight or too loose.

Did the new motherboard have all the Device settings / Machine settings that the original motherboard had?

Find an inexpensive white cloth and wipe the Y-Axis rails where the machine runs to see if they are dirty, sticking, and contributing to motion symptoms.

The rails are clean and no problem moving the head with power off. I am going to try swapping motor drivers to see if one is bad.
I have replaced mother board and controller and there is no change in action. The Y sensor seems to be working but I will replace it as soon as it arrives. The head does not stop when it activates the y sensor. It acts as though it isn’t working although the light on the mother board lites when i activate the switch with a screwdriver.
I am at a loss at this point and i am in the middle of a very important job. A bond fire comes to mind.

Thanks if you have any other suggestions.


Just swapped motor drivers and nothing changed. Still y doesn’t work right.

Can you do a manual home… meaning put the head furthest position from home and power it up…

You have to manually toggle each home switch twice. Press <esc> to stop the machine from homing.

You can also go to Z/U → Diagnostics to see if the machine actually sees the Y home switch. My Y home switch was active in this photo.

My WP input LED showed that the chiller was running, but I got a water protection error… Even through it showed up on the LED, it wasn’t seen in the diagnostic screen… It failed within the controller, somewhere… Ended up disabling that input.

Good luck


Diagnosis shows both limit switches working. Both red.

Meaning they are active?

Generally they shouldn’t both be active…

If you move the head away from home, do they go out?


X goes wherever I direct it to go. Y has a mind of it’s own and makes a grinding noise. The noise is not being generated from the rails but as though it’s getting two signals in different directions. it goes up and next arrow it goes down and stops. There is no rime or reason. I have checked everything I can think of but no luck. The X head goes home and does’t it’s dance with the sensor and then after a few minutes it heads on it’s own to about the middle of the upper bed.and parks. Very strange because I did not direct it to do so. Magic.

I posted a question…


Some more troubleshooting questions…

Test basic movement

Since your homing is not working, just bypass homing for this step: When you turn the machine on and as the homing cycle starts press the ‘Esc’ button on the control panel to cancel the homing cycle. You should then be able to jog in both axis. (but don’t jog to the very ends of the axis otherwise you will crash since the soft limits are not active):

  • are both axis moving smoothly and in both directions according to the keypad?
  • do they sound ok?
  • try pushing the movement harder - manually increase the speed (using the ‘Speed’ button on the Ruida control panel) to a higher value like 300mm/s, can you still move smoothly in both directions? If you hold down both X and Y jogging buttons at the controller at the same time does the laser head move smoothly at a 45deg angle?

Test scale:

  • try jogging with measured Moves from LightBurn, are the moved distances correct as expected? (manually pulse, move, pulse, measure distance between the spots)

Test home limit switch, and deceleration:

  • set the jogging speed down to 50mm/s, then for each axis individually manually jog towards the home switch, and while the machine is still jogging manually activate the home switch for that axis (might be easier with two people to safely test the Y-axis or use a measured move of 300mm which gives you about 5 sec to try and activate the home limit switch, slow the speed to 30mm/s if needed). The hard limit alarm should show on the panel and movement should stop very abruptly.

Send us your machine settings:
With the machine connected, please go to Edit>Machine Settings, ‘Read’, and ‘Save to File’, attach that here.

Fisk 8-20-23.lbset (14.3 KB)

Any clues? Did you get the file you needed?

Sent the file. Also got in a new prox switch for the Y and will change in case it is not working although all indications is that it its but I have seen many parts act correct and are not. We will see. Any info on the file A sent?

One thing that stands out is ‘Homing speed’, which you have set at 250mm/s which is too fast, and should be around 30 to 50mm/s^2.

X responds correctly, Y almost never goes in the direction I send.

Both lights are red but Y doesn’t respond as it the switch is working. I just got a new one and will see if that helps. Tks

Just made an interesting discovery. I’m down to checking wiring as much as I can. On the mother board are two three pin connecters which drive the motors. 3 pins one is 5 v and the others are labled cw and ccw. I switched them X and Y to see if the bad action would switch from Y to X. It did exactly that. It appears there is a distorted signal being sent to pins 4 and 6 to the
Y motor. I even switched the motor drives to make sure. Sure enough the bad signal is being sent thru pins 5 and 6 of the Y connector. I have not been able to determine the source of the signal for the pins so I don’t know if it is the mother board or not.
Maybe you can tell me before I set that bond fire.
I would really appreciate your input. I am really in a pickle.

These top group of pins are control pins… power is supplied to the motor driver via it’s 24V connection in the lower set of connections.

They are ttl signals to control step rate and direction. The 5V you are referring is probably wired to the ENA (enable) pin.

Sounds like you have a dead motor driver… is the light on it green?


I swapped motor drivers and the Y motor works fine. I suspect the mother board but could be wrong. When I swap the output connectors at the bottom right of the mother board the Y motor works fine. Switch them back and the Y motor does not work properly.