Bit depth doesn't match error

[caklmk]

I am getting this error more and more often, but not always. It usually happens on the second bit change on a three bit carve. I can select re-find which always returns the same message. When I select continue the machine will continue with the carve, but will sometimes be carving 1/16 or more from touching the board. I have formatted the memory card and re-flashed the card to no avail. On one occasion it happened on a carve which only required the carving bit. I installed the bit, it did its routine, came back to the home position, and gave me the bit depth doesn't match, without my even touching it. Any suggestions.
Thanks,

[Digitalwoodshop]

This is likely going to come down to one of the following...

1. Dirty Z Rails or rollers especially the bottom half of the keyboard side of the Z Rails.

2. Bad FFC Cable or going bad as in the copper touches then not...

3. Dirty Z Encoder or Z Encoder wheel spinnning on the shaft of the servo motor.

But likely dirty Z Rails is the most likely to include dust in the Z Belt cogs.

Is the 3rd bit shorter where the head is needing to go down further toward the board into dirty rails?

AL

[sw123man]

I had the same problem awhile back my solution was the following:
Most likely cause is that the bit is not touching the bit plate during set up. With the CW off move the truck over by hand to insure free movement and that the bit plate will pop out easily. Give the bit plate spring a good shot of air to blow out the dust and then spray in some WD-40 into it. Blow it out again with a rag to catch the spray out. Also check to insure the wires from the cut motor are tucked back into the corner and are not hitting the back of the Z motor.

[caklmk]

Thanks Al, When you asked if the 3rd bit was shorter, which it is, I knew what was wrong. I replaced the bearings in the z truck and it moved up and down like a dream until I hooked up the belt and detected several rough spots when moving it up and down. I am waiting for a new z truck motor assembly. I'm sure that it is worn out as it has over 950 hours on it.
Thanks again, caklmk

[Digitalwoodshop]

See if you can add a new Z Belt also... Just to save on shipping.... I have damaged my Z Gearbox plastic gears JERKING out the flex.... So a inspection of the old Z might show rough gear teeth... know you can buy that gear as a replacement part and have a backup.

Good job,

AL