Festool Plunge Saw Electronic TS 55 EBQ HK 55 230V
This electronic is the brains behind the saw and is there to help control the saws speed and function, over time electrics will deteriorite and will no longer work as they should, at this point you should replace this part.
Please see below for all applicable models, please match your machine's TNR number rather than the Model number to ensure you are selecting the correct part.