The TBC30 is job-specific car top interface circuit board for both hydraulic and traction controllers and if the exact replacement is required then the NS (Serial Number) of the controller must be provided The one supplied is populated as per the image and is suitable for most applications. Before installation check J5, J6, J2 of the old circuit and ensure they are the same on the new circuit. Also, check R1, R4, R5 and R6 these are zero ohm resistors that are jumpers and must be cut out if required.