ABL Servo probe issues

[Roxy]

It is very possible you have a bad servo. But we can do a few things to get more confidence of that before you go to the trouble (and wait) to get a new one. M280 does not mess with your probe angles. And I had to double check but the EEPROM has nothing to do with servo angles. Those values are declared:

#if HAS_Z_SERVO_ENDSTOP
const int z_servo_angle[2] = Z_SERVO_ANGLES;
#endif

which means they can never change. (Unless you change Configuration.h and recompile the code.)

Lets do this: Do a M280 to set the leg position halfway between the two angles you have defined. And then measure how far from the bed the lowest part of the probe is. Let it just sit there for 6 or 8 hours and lets see if it moves. It might be easier to just raise or lower the Z axis so a coffee cup or something else just barely slides under it without touching it. That way you can easily check things accurately without bumping anything.

And once you get set up like that, give it an M280 P # but with no S parameter, it should tell you the servo angle. Over time, this command should keep returning the same number (to prove nothing has been done to tell the servo to go to a new angle) If you see the servo move, for sure we want to give it an M280 P # with no S parameter and see if the servo subsystem thinks anything has changed.

My guess is we might see the servo move for no good reason. And if so... the servo needs to be replaced.