Although manufacturers ship only products that have passed multiple pre-shipment inspections, some products still fail in the field, in which case further inspection may be needed to trace the cause of the failure. The products analyzed in this study included auto disc changers that were 'dead on arrival', presumably because of defects that were slight enough to pass the existing preshipment inspections but had progressed into more serious problems after shipment,causing the product to operate incorrectly. The current consumption value during operation of the auto disc changer was measured and its waveform was evaluated using the RT method to obtain a quantified operating function. The results suggested the possibility of pre-shipment detection of devices that might fail in the field.
