Apparatus for testing functionality of a printed circuit board used to control operation of a printing press, including a plurality of input switches for providing to the circuit board test input signals simulating function control signals from a printing press control input, the function control signals controlling a plurality of functions of the printing press; a plurality of test loads simulating printing press loads for receiving from the circuit board output drive signals developed in response to the test input signals; and a processor for controlling operation of the input switches and for monitoring responses of the test loads in response to the output drive signals, whereby proper functionality of the printed circuit board in response to each of the plurality of function control signals is analyzed under simulated conditions of an actual operating printing press.