[Solved] ABL & Z calibration failed. Fried Einsy Board?  

I assembled lately a new MK3S+, which worked perfectly fine until yesterday, (has around 11h of printing time

OK, so a fundamentally sound build but something has come loose...

This doesn't read like an electronic problem but pull and replug all the connectors on the Einsy board in case one is loose or dirty.

If you have access to a working printer, make your next print this:

https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus

It MUST be printed in Prusament PETG or the spring tension will be wrong.

(If you don't have access to a working printer set up as in the build manual and make this your first print.)

Why? Because the belt tension figure on the LCD menu is a measure of the resistance felt by the stepper when moving the axis. On a correctly set up machine this does equate, roughly, to belt tension but other things can affect mechanical resistance.  If the X or Y axis is glitching the calibration points cannot be located accurately.

So for the X and Y axes:

First, with the power off, move the axis by hand; is is smooth? Does the resistance stay the same over the whole range?

Clean and lubricate the smooth rods, check they are not damaged/scratched. Check the idler pulley is not clogged, out of line, or damaged (loosen the belt and try turning it with your fingertip, is it smooth?)

With the belt loose try turning the stepper motor by hand; is it smooth?  (You should feel the stepper pulses, that's all.)

Check the motor-pulley grub screws are correctly aligned (one on the flat, one on the side) and tight.

Retighten the belt until it just begins to make a low musical note when plucked...

... then use the printed meter to optimise the tension.

And after all that do a factory reset and recalibrate.

Let us know how you get on.

Cheerio,

RE: ABL & Z calibration failed. Fried Einsy Board?

Thanks for your answer. I retightened everything, the pulleys and belts are not loose and comparable to the other MK3S I worked with. Also there is no special resistance along any axis, so I think mechanically it should be actually fine.

The following points lead me rather to the conclusion, that there is something going on with the Z stepper drivers:

- The wizard, even after the factory reset, tell definitely "Selftest error! Please check: end stops, wiring error Z"

- Why does the X-Axis move continiusly move upward after(!) arriving at calibration point 2? Both Z lead screws move, so I think it is not a single motor fault. It still does its left an right searching move as it would do on the build plate while moving upwards, really strange.

- Auto home just works normal below a certain Z height, above it will move up to the end stops instead of going down.

I'm really confused, I think I will ask my company if I could swap boards maybe and see if it still has the same issue. I couldn't explain why it would do such things only based on some mechanical issues.

What do you think about these points?

"Selftest error! Please check: end stops, wiring error Z"

It's time to take this at face value. They clearly work but feedback seems to be missing. Double check the Z motor connections.  You probably have wired-in leads but if they are plugged in at the motor end check there too.

If the problem persists contact Prusa Support:   Log into your Eshop account, navigate to support and live chat is at bottom right in most browsers. If not you may need to disable your ad-blocker temporarily.

Cheerio,

RE: ABL & Z calibration failed. Fried Einsy Board?

Ok I think I have an idea now. Lately, auto home doesn't even work on the lower Z range, like it did before.

I checked the Handbook for the "Wiring Z" error message, it says a malfunction of the PINDA is possible.

The red LED of the PINDA still turns off, when I put some metal under it, but in the Support menue -> Sensor info, the PINDA value is fixed to 1 (which indicates the triggered state, hence the absence of the downward movement while autohoming).

My guess now is, that there might be some cable break of the PINDA, which would explain why it inconsitently switches between case 1 & 2 and didn't autohome sometimes, because the cable got slightly moved.

I will try to get my hands around a new one and see if this fixes the problem 🙂

RE: ABL & Z calibration failed. Fried Einsy Board?

Unfortunately I can't edit the post anymore, but a short update:

I unscrewed the cable holder on the extruder and wiggled the cable a bit, and the PINDA state toggles between 0 and 1, if I move it. When I hold it in the "0 position", Auto homing works. So I think it is a pretty clear case.

What astonishes me is the fact, that the PINDA LED still switches, although the signal is constantly 1. So there is some logic build into the PINDA itself?

It sounds like PINDA is working - check it's inserted correctly into EINSY.

Somewhere your sensor/feedback feeds are failing - contect Prusa Support chat.

Cheerio,

RE: ABL & Z calibration failed. Fried Einsy Board?

Yes, the PINDA does work, but the cable is simpy broken, as it is continiously putting out 1 in certain positions. When I have it in a state where it shows 0, then it works as it should and switches only to 1 when a metallic object is put beneath it. The connector is definetly not loose on the board. 

I don't know if it is a NO or NC inductive sensor, but I think it is easily explainable, that 0 is a active signal put out by the PINDA (red LED is on), while 1 is the default state when there is no connection (red LED off). This can be also seen when the PINDA is completely unplugged, the sensor info menue shows then 1 too. So everything adds up and makes sense.

I will try out a new PINDA as soon as possible, I'm optimistic it will be sorted out then.

Contact Prusa Support chat.

Very often they will supply replacements under warranty.

Cheerio,