Method for inspecting a populated printed circuit board, particularly for inspecting solder joints on the board and a system for working this method

A method for inspecting areas of a populated printed circuit board, comprising the following steps:

• continuously heating the board until a set temperature is measured at a target point on the board;
• defining a measurement validity time range that begins at a time after heating has stopped, and includes all subsequent times wherein a measured heat difference can be used to detect insufficient or irregular soldering material;
• recording a thermographic image of the board, the thermographic image consisting of instantaneous temperature measurements as a function of position on the board, at an instant in time within the measurement validity time range;
• and
• analyzing the thermographic image by detecting temperature differences between a predefined standard thermographic image and the thermographic image of the board.