In mass‐production of PCBs, visual inspection of soldered joints has probably been the last major operation still performed manually. A system has been designed to ensure that the accept/reject threshold is firmly held at a pre‐set level, to detect defects on or under the surface, to identify these defects by type, severity and precise location and to carry out the inspection at high speeds with full automation. The system's operation is based on a laser firing a pulse of radiation onto a solder joint, an infra‐red detector monitoring joint temperature changes, a programmable XY table, a computer storing the thermal signatures of acceptable and rejectable joints and a device for programming, displaying and recording all necessary data. Enhanced reliability and cost savings are possible with this automated process of inspection.