XYZ calibration failed Bed Calibration point not found  

XYZ calibration failed Bed Calibration point not found

Hi all,

Trying to run the initial calibration steps on my MK3S.  It is failing on the Z calibration step 1, with an error of Bed Calibration point not found.

Here is a video:

https://drive.google.com/file/d/1dzmn_01Vtl0E4RfuRn--6XEl6JvyjgOy/view?usp=sharing

I've noticed when looking at it closely there is a little bit of skipping as it searches for the calibration point, but it doesn't do that when manually moving the axis.

I've tried the following -

1. Moving the PINDA sensor, both higher and lower with no effect. I've tried putting the nozzle against the bed and lowering the PINDA sensor until it touches a zip tie. I've tried a dime as well and a license. I've even tried lowering the PINDA sensor further than the nozzle just to see if that would make a different. Fails each time.

2. Re-flashing the firmware to an older version (3.8.1 from 3.9). Doing a factory reset, and then reflashing to 3.9. No effect.

3. Tightening the X belt (it looked a little loose.) I've now got belt values of 240 for the X and 260 for the Y.

4. Unplugging and re-plugging in the PINDA sensor

5. Testing the PINDA sensor with a piece of metal (both a spatula and a screwdriver.) It changes from 0 to 1 when I move the metal close to it (it feels very close but its hard to tell.)

6. Checked all of the zip ties and moved all the axis manually to make sure there isn't any issues.

I spoke with Prusa support and sent them the above video. The support person I spoke with believes it to be a faulty PINDA sensor and is going to send me a new one. I'm not 100% sure its a faulty PINDA since it checks out ok. It is worth a try though.

Its going to take a few days for the new PINDA sensor to arrive. Does anyone have any ideas about something I could try in the mean time? Or any ideas on how to fix this?