Lowrider Stopped Moving

LowRider CNC Troubleshooting
1

So today between jobs my lowrider stopped moving. It had been cutting well and nothing during the cuts seemed off. Then it suddenly stopped moving.

The screen comes up and the board looks like its moving normally. I can connect to the board from CNC.js and its responds to commands.

If I use the screen to issue commands X and Y act like they are working even though no motors turn. When I try to move Z I here a slight click from the stepper and the machine resets. If I try a home command I get a System Halted Please Reboot Message.

I’ve got an SKR 1.3 with TCM drivers. I’m using sensor less homing and no endstops. Machine was working happily this AM.

What I’ve tried so far:

  1. Check Power Connections to the Board, look good and measuring 12v
  2. Swapped out Power Supply
  3. Disconnected Z Steppers
  4. Disconnected All Steppers
  5. Disconnected Probe
  6. Unplugged Z Drivers (TMC Connection Error on Screen)
  7. Disconnected Raspberry Pi
  8. Run M501 & M502.
  9. Checked Onboard Fuses.

Nothing seems to have an effect.

I’m out of ideas except maybe flashing the firmware. Any ideas?

Thanks.

2

Check that you are still getting VMOT power. You can check this (carefully! Don’t short it out!) on the stepper motor blocks.

That’s for an A4988 but a DRV8825 or TMC driver will be the same. You want to be sure that you’re getting VMOT over the 2 pins in the top right.

If you are not, then start looking for blown fuses. Pretty sure those are just the 2 Mini-ATO style fuses next to the power connectors. Make sure that nothing has shorted the power lines before replacing any fuses.

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3

I haven’t checked the VMOT power yet but I did check each controller digipot voltage and all were at 1.1V which is correct. I also checked fuses and both have good continuity on a multimeter.

I’ll check the VMOT in the AM when I have a fresh head.

I also reflashed the board thinking that might help.

So far no luck.

4

Ok I’m impatient… VMOT is 12.22v on each of the controllers which matches the input voltage at the main supply.

5

I also tried pulling all controllers which results in no errors but if I add any controller in any slot the error returns, always on Z.

I’m starting to suspect the board at this point.

6

Ended up swapping out the board… seems to work ok now.

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7

Ok so I figured out the problem… as usual it was user error.

After installing the new board the unit was working until I ran my startup script again and it began to fail the exact same way.

Turns out that I had inadvertently put a m92 (steps per unit) instead of a g92 (set coordinates). Followed by a m500 saving it eeprom.

So my m92x0y0 was giving either 0 or infinite rotations per mm.

Amazing how one character can lead to hours of troubleshooting. Hopefully my dumb mistake helps someone.

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8

Oh. Man. So glad you figured that out. That would have been so hard to figure out.

I have done M92 instead of G92 before. It was pretty funny to me when I realized what was going on.

Marlin should probably not allow that getting set to zero…

9

Yeah even worse is that I thought the firmware wipe had failed but had forgot to do the factory reset after flashing. Would have saved me a full rewire of the board. Oh well lessons learned.

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