can anyone tell me what pieces are mounted under it to the actual foot pedal that react with the circit board in side because it looks to me like I might be missing a piece?
There is not a "piece" as it were that the Expression Treadle works with on the RP255. If it stopped working I would run it through the Pedal Calibration:
Also if that does not work, try a factory reset:
ATTENTION: Performing this function will erase all user-programmed data. All
such data will be lost forever! Be sure you want to erase the memory and start fresh
before continuing with this procedure.
The procedure for performing a Factory Reset is as follows:
1. Press and hold the Store button while powering up the RP255.
2. When the display prompts you with FACRST, release the Store button, which is now flashing.
3. Press and hold the flashing Store button for 3 seconds until RSTORD appears in the display and
release (The Factory Reset procedure takes approximately 20 seconds). The Expression Pedal
calibration procedure now commences.