Depth of cut will not adjust

Hi folks; I have had my x carve for about a year and did not have any problems with it until the last couple of days. First; the Dewalt 611 went out. I purchased a new one, and installed it into the machine; as described in the instructions. I tried to do a cut with a 90 v bit for a project that I have made several hundred times (same Easel project). I noticed immediately that the letter were being cut way too deep. I had the DOC set at .03 and the depth of cut was at least .125. I then tried to adjust the DOC to .02; the DOC still cut at about .125. I tried to adjust it way down to .001; DOC still at .125. I then switched projects and tried a simple line cut with a 1/16 down cut bit. Same results; the machine will not adjust the DOC lower than about .125? Seems like something when wrong with the machine program? Any ideas about what is happening here?

How are you setting Z zero?

I am using the z-probe; albeit, I have also tried it manually with the same results. As you imply; it appears that zero is somehow off in the machine. Any way of re-calibrating the zero setting? I have tried everything I can think of including reloading the firmware. Any help is appreciated.

Is the pulley on the Z screw tight?
Possibly the grub screws have come loose and the pulley is slipping on the acme screw?

I checked all the belts; they are tight. Grub screw is also tight. The machine cuts fine and I can achieve zero by placing a 1/16 in piece of card board under the z probe. Again, it appears to be a problem with the machine setting zero?

If you’re zeroing manually (i.e. Bit touches workpiece & you set zero), your zero will be wherever it was when you set it. It has to be.

You stated in your first post that the first pass is always 1/8", no matter what. In your next post, you said the machine cuts fine if you cheat the probe by 1/16".

When you set your zero, that will be your zero. If the machine “changes” or “loses” that zero, there is most likely a mechanical issue or a procedural one.

.125 was an estimate. The machine; as stated does not set zero. It remains appropriately 1/16 lower than zero using the z probe and will not adjust any high. Using a 1/16 shin to fool the machine is a stop gap.

Hi Ed, your posts referenced a few things that all may have different causes. Just trying to clarify.
If the only issue is setting zero with the probe, you’ll need to run the probe setup again and enter an accurate thickness. It may also be an issue with your steps/mm. If you set Z zero manually, and when you jog back zero you’re off, you have a mechanical issue.