I am trying to get a local guys A machine (it has been upgraded with the A907 Z pack and CarveTight chuck) that he wants to sell. It was in storage for almost 2 years. As far as I know (not assuming anything with that statement! it was working when he put it in storage.
After getting it all cleaned and lubed up and running all of the sensor and axis tests the first test carve ran without any issues. Since I have it set up in the shop of the maybe future owner I told him to go ahead and carve up some Christmas ornaments that he wanted. His next carve ran good including the cut out.
Problems for then on: A long winded one but wanted to get as much info in as possible.
Next carve ran good but when it stopped and was suppose to ask for the cutting bit it went to Z stall message instead. Modified MPC and ran the cut path with no issues.
He then ran 2 more and on these the carving depth stared changing. The depth started getting shallower as it got to the highest parts of the pattern and then leaving the top surface of the board as not carved for those areas and as the pattern goes lower back into carving the detail.
Today I went over and reset the FFC cable and double checked all of the other connections. FFC did seem a bit out at the back of the Z truck. Ran a small carve region test with a 2" x 2" region with a cut out of the center. All ran well. I then loaded up one of the prior carved pieces with the high spots and started it over. When it got to same area of the flat carve it was doing the same thing. I aborted and modified the pattern height to lower the highest spots. In designer it showed them to be 0.01 depth. I had to take the height down to 75. The re carve ran good and no Z stall when stopping for the cutting bit.
I ran the board thickness calibration and modified the rest of the MPC files to lower the height setting. All prior uploads were done as a "normal" carve quality and since he is carving these in walnut and cherry I selected optimal.
His next carve went the opposite way. As it got 1/3 of the way into the pattern it started going deeper and finally into the bottom of the jig.
Any insights for what to look at next? My thoughts would be the Z motor ( I did remove the back cover and it was clear of dust and the clear disc was in good shape) , head termination board and the z motor electronics board.
PS: It is Christmas time in Colorado Ya Know!