Last updated on June 15th, 2017 at 10:47 am
While printing ABS before Christmas, a large print lifted at a couple of spots and broke the mount for the Pinda. I did not have a spare for the mount but procured a Prusa design part using a local 3D Hubs service. After replacing the mount, I could not get the i3 MK2 to run through calibration.
I tried to get support from Prusa Chat but found the whole process very lame as staff had too many chat lines on the go simultaneously. They were away servicing other for up to 30 minutes. It was very frustrating and quite unlike a dedicated tech working with you to wrestle any problem to a successful conclusion. I quickly realized that the Prusa support was useless to pursue and that I was totally alone in wrestling with my issue.
Repeated attempts to calibrate the z axis were met with varying degrees of success, mostly poor and inconsistent. Having a bright light over the printer, I had never realized that there is a red led that is constantly lit on the top of the Pinda. When a ferrous blade was placed under the Pinda, the light would extinguish. I quickly determined that it proved the Pinda was operational.
Many days and many tries passed when I noticed that when I moved the extruder head from left to right on the X-axis that the red LED on the Pinda would extinguish half way along. Seeing this I wiggled the wire bundle exiting the head and found the LED to be intermittent with each wiggle. Investigation revealed that the black cable jacket containing three Pinda fine wires had not been tough enough to prevent the blue lead from breaking and being intermittent. It appears that the cable retention clamp on the Pinda mount 3D printed part was sharp and tight enough such that when the Pinda cable was removed or replaced, the one of the wires had been cut internally. No external jacket or internal wire insulation damage was noticed. The wire cut was about 1 1/2″ away from the Pinda body and gave enough space to open the jacket and splice in a short length of similar sized wire.
I set up the Pinda per the Prusa Manual and ran through the XYZ Calibration steps which produced Calibration success on the first try. (When the Pinda wire was damaged, Calibration points were sometimes ignored, Calibration attempt times were very long, Z Calibration efforts resulted in damaged bed surface, etc, etc.
The lesson learned: “If the bed is level and perpendicular yet the printer will not Calibrate and produces erratic results, ensure that the Pinda LED is always on – unless triggered at a Calibration point”.