Unable to set up nozzle height. Z will not drive below -1.39

[Tog]

My printer has behaved itself until this afternoon when it started to have printing problems caused by the nozzle being too high.
The printer uses a 3DTouch probe and I attempted to do a calibration using https://www.geeetech.com/wiki/index.php ... alibration which has previously worked.

The problem:
When trying to drive the nozzle down towards the bed to get the nozzle height to equal A4 paper thickness, Z stops at -1.39 and won't drive any further.

Things to note:
1. The Z drive moves up and down freely.
2. I raised the bed by 4mm to see if it was a physical issue with the Z drive, no change to the symptom.
3. I reloaded the firmware, no effect.
4. I had made no changes whatsoever to the firmware. The fault occurred between 2 print jobs, it was working, then it wasn't.
5. The 3DTouch probe operates, homing brings it to the same height every time and it stays retracted afterwards.

[Gingko]

Is there no change when setting different Z offset?

[Tog]

Is there no change when setting different Z offset?

Setting different offsets makes no difference. The offset reports as having changed to the new value but I still cannot drive down below -1.39

I've now upgraded the firmware to 1.1.8 which also makes no difference.

[Tog]

Is there no change when setting different Z offset?

Setting different offsets makes no difference. The offset reports as having changed to the new value but I still cannot drive down below -1.39

I've now upgraded the firmware to 1.1.8 which also makes no difference.

Here's a thought, I haven't reset the memory to defaults. Does updating the firmware do that anyway?

[Tog]

Is there no change when setting different Z offset?

Setting different offsets makes no difference. The offset reports as having changed to the new value but I still cannot drive down below -1.39

I've now upgraded the firmware to 1.1.8 which also makes no difference.

Here's a thought, I haven't reset the memory to defaults. Does updating the firmware do that anyway?

M502 followed by M500 made no difference

[neowinx]

You could try disabling the soft end stop by sending

M211 S0

That supposedly has to allow you moving the nozzle below the Z offset

If that doesn't work you could try bring down the Z axis as low as it allows you and then resetting the Z coordinate to a new height like this:

G92 Z10

That will set the Z coordinate to 10 so it won't stop you to go further down

Be careful though.. both of these methods allow your printer to crash your nozzle to the bed. Move at 0.1 mm and keep a finger in the power switch at all times when doing this

Once you have the nozzle at the desire height calculate the distance from the offset in order to set that with M581 and M500 commands respectively

Good luck!

[_kaktus_]

Hi


You need to know one more important thing.
Power off when the stepper motor is running may damage the stepstick module.

[neowinx]

Hi


You need to know one more important thing.
Power off when the stepper motor is running may damage the stepstick module.

wasn't aware of that!

Good point, thanks mate!

Although moving down the nozzle at 0.1 mm per "click" should be safe so no need to power off I guess

[_kaktus_]

Hi


In my printer, I replaced the springs that hold the worktop.
The springs I used are not as hard as the original ones. They are lower. They are also wound differently. They are conical in shape. This special shape ensures that they do not bend sideways.

But to the point.
Now that the springs have been replaced, when I lower the head below zero, the entire worktop bends softly to allow the mechanism to be lowered.

In general, I consider this to be a safe operation.

This springs is one of three original elements that I replaced with others. They were relatively inexpensive.

[Tog]

Sorted, it was a lazy copy/paste into configuration.h on my part
Without checking (duh) I just copied in a number of lines including this #define Z_PROBE_OFFSET_FROM_EXTRUDER -1.4
Not even sure why I would have changed that, I'll blame the kids...
Rookie error, sorry for wasting your time