Quoted from pinballj:
The treasure chest now fully opens and closes now!
From the Proof of Concept, I had to make the following changes:
1. Change the 3d printed bracket for mounting the micro switch in an angle (similar to the microswitch that already exists toward the playfield)
2. Make a new metal bracket to replace the "fixed position lid bracket".
3. Using a m3 threaded end rod for the servo linkage.
4. Adjusted the open angle in software
5. 3d printed a new cover for the solenoid gate behind the treasure chest to make room for the hinge
I am going to test this a bit (finally have the game back together! I have been having JJPOTC withdrawls lol), before updating the instructions and BOM for building this.