Preventive maintenance screws up PINDA  

Active Member

I have an i3 MK3S which is a year old and has been printing great!  I decided to do some preventive maintenance and went through the list on the Prusa site.  I tightened every bolt and screw, including all those on the back of the hot end.  Full cleaning and lubrication of rods.  I opened up the Einsy-case and tightened all the screws.  I found that the Y belt was a bit loose and tightened it up.

The problems started when I ran the Z Calibration.  The second calibration point the nozzle didn't stop and went all the way against the print bed.  The PINDA had not triggered.  Strange, I thought.  I lowered the PINDA by a tiny amount and reran the Z calibration.  Now it goes past the second calibration point but does the same thing on the 9th and final calibration point.  I checked the PINDA sensor and it read 0, even with the nozzle against the bed.  But it seemed flaky and would go to 1 if I moved the PINDA at all.  Also it only seems flaky when the hot end is at the top right (last calibration point).

I tested the PINDA by putting a screwdriver up against it and it seems fine.  No flakiness observed.  But this is with the hotend in the middle.

I am looking for suggestions on what I might have done.  My first idea is that tightening all the bolts on the back of the hot end was not a good idea.  This might have pinched the cable from the PINDA.  Second idea is that there is a partial break in the PINDA cable, anywhere along its length.  Third idea is that by opening up the Einsy-case I somehow messed up the PINDA connection.  I will open it up again and check the connection.

Any ideas on what the problem might be?

This topic was modified 1 month ago 2 times by gibell
Posted : 17/09/2020 3:50 pm
Active Member

I should mention that I lowered the PINDA to the same level as the nozzle and the printer passed the Z-calibration.  But I still think there is a problem, I don't think the printer should be run with the PINDA this low.

Posted : 17/09/2020 4:56 pm
Active Member

A quick update on my printer, in case anyone else has a similar issue.  It seems to be OK now, I believe the issue was a pinched wire in the PINDA at the back of the hotend.  I checked the connection of the PINDA to the EINSY board, and it was fine.  I took off the back of the hot end, I didn't notice any pinched wires but I reattached it less tightly.

The printer then passed Z calibration after I lowered the PINDA.  Whereas before I was running with a Z adjust of -0.5 now it is -1.5.  This seems a bit odd, but it seems to be working fine now.

Posted : 20/09/2020 12:33 am
Trusted Member

glad I read the last post I was going to suggest it may be a short, same thing can happen with the LCD , fan wires, thermistor wires etc,, sometimes it requires a replacment. eventually some of those components wires will wear and need replacement, so far its mostly been fan and thermistor for me but I keep extra PINDA's around also.

Having to re-adjust Z is not odd at all after a good checkup and screw tightening its normal that it might be different.

Glad you got things going again



This post was modified 1 month ago by Dan.p12
Posted : 21/09/2020 1:13 am

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