The toolhead board assembly is an assembly that includes 2 PCB boards (the extruder board and the interface board) and connecting cables. The cables are fixed to the connectors with silicon glue.
Power OFF the printer before doing any maintenance work.
Note: Use a hair dryer to heat the silicone glue that applies to the connectors before disconnecting it to prevent damage to the connectors.
Should you come across any issues, first retrace your steps and check all connections to try again. If problems persist, contact the service team for further assistance.