I have an Illinois Getty that runs fine and keeps time when under power. When the mainspring is close to completely runnning down the watch overbanks. Here's what I know:

- All serial numbers match.
- All jewels appears to be original and untouched.
- The pallet stones are firmly seated and look like they've never been re-shellacked.
- The guide pin is vertical, and the pallet fork tail is straight.
- The roller jewel is firmly seated and looks to be the correct length. It is not leaning or off-center. It is not chipped or missing a corner.
- The roller table is running flat and looks like it's never been pulled off the staff.

I've adjusted the guide pins incrementally in tandem through their full arc, but the watch still overbanks. Suggestions?

Eric,
Check endshake in the pallet and balance.
Hold the balance over one side and using pegwood gently see if the pallet can toggle past, then repeat the other side