Before you remove the chain, I suggest you slide the spring loaded megatron tapped resistor back and forth to see if that loosens up any built up debris then press pull button.
The megatron is a green precision laser trimmed potentiometer as seen in second photo showing the pull chain.
Just...
Trip lever is missing. Activating rod should not be poking thru base. Seems the base was reassembled improperly. Recommend you contact Babolat or Tennis Machines (St. Louis) for assistance.
The question you should be asking now is, what's next for this aging behemoth? My guess is limit switches or motor brushes. Keep fingers crossed for a few months of flawless operation.
Fapostolis: if by "single" potentiometer you mean the one next to the two red capacitors, then you turned the correct "Offset" adjustment screw. If no change in measured value, then next step is to check gray ribbon cable for continuity. If all connections measures well, then the bad news is it...
Fapostolis: The 2502 has a full wave wheatstone bridge loadcell configuration. Good luck finding a replacement or getting Babolat to give you the OEM name.
Could be string debris inside clamp jaws. Irwin is right, you will need to disassemble the clamp to clean out the debris.
If not debris, then could be a broken spring that needs replacing. You can send the clamp to Stringmachines.com. Call JC at string machines and they can take care of this...
Your Star 4 is certainly sick, it's turned into a Star 5.
Call JC and tennis machines (www.tennismachines.com) and see if they have replacement Star 5 parts.
Babolat stopped making Star 5's a few years ago, so no telling how many spares are still available.
Take care, stay well and safe.
What is your Star 3 doing or not doing?
Very seldom is the problem on the Motherboard.
Given the age of these venerable machines, the part to replace is the Megatron. ($175 to $250). The Megatron is a precision laser trimmed potentiometer that measures the compression of the reference spring...
Paul: Thanks for all your help. The power point file was just what I needed. After a short time and some trial and error steps, I got everything working and re-wrote the instructions to clarify a few confusing issues.
Thanks to Paul for sharing his knowledge and expertise on this forum. We...
Paul: When you have a spare moment, would you mind sending me the instructions for calibrating the Mono Screen Racket Station to abllee@verizon.net?
Kindest regards, stay well stay safe!