Joystick problem

[[SH...]]

An online programmer asked me about this. How can I help him?

IMG_20210419_214600.jpg

[[Ja...]]

Best thing would be to ask Zeiss technician for resolving it.
This is just a suggestion. If only the plastic knob on the top is broken, then get some aftermarket similar knob and replace it. I don't know if there is lock ring to secure that knob if so be careful when trying removing it.
If the inside metal rotor (rheostat) is broken or loose, then you absolutely need Zeiss to help replacing the rheostat.
Temporarily you can use speed settings for the program to control it.
lower or increase it when starting your run based on what the current knob setting is stuck on.

[[Ry...]]

What exactly do you mean by "Knob Got Loosen"?
Is it spinning and not controlling the speed any more? Or is the "line" not correctly lined up?
Either way, take a small screwdriver, or a sharp fingernail and pry up on the cap on the top of the knob. The cap is what the white line is printed on.
Under that you will see a small lock nut. This may have come loose. As well, if the knob was turned to hard, usually happens in a panic when the probe is about to crash, the knob gets grabbed and turned down which causes it to spin on the shaft, putting it out of proper orientation.
Undo the nut, remove the knob and check for damage to the plastic splines. If they are not bad, turn the shaft either to 100% or 0% and line of the knob and cap line to that part. Tighten the screw and re-install the cap.
Good to go.

HTH
Ryan