Abstract: A test fixture of the type that requires repeated manual lifting of weights in a drop-tube for performing an ASTM drop weight test, is provided with a computer automated pneumatically powered lift mechanism. The lift mechanism for the weights responds to a series of computer generated signals that are applied to a set of electropneumatic actuators for driving pistons to lift and drop the weight. Associated with the lift mechanism is a set opto-interrupter devices that generate a position signal representative of the position of the weight to be dropped as it ascends in the drop tube. In use the computer is provided with a desired drop height and essentially continuously compares the position signal with the desired drop height and releases the weight in the drop tube to impact a sample material when the position signal equals the desired drop height.