System comprising, - a ball grid array, BGA, component arranged on a circuit board; wherein the BGA component comprises a reference solder contact which is connected to a reference potential; wherein the BGA component comprises a plurality of solder contacts (121, 223); wherein the solder contacts (121, 223) are connected to the reference potential in each case via an internal diode of the BGA component and via the reference solder contact; and - a test apparatus for checking a solder contact (121, 223) of the BGA component; wherein the test apparatus is designed, - to determine a plurality of measured values of an electrical resistance of a corresponding plurality of connecting passages for the corresponding plurality of solder contacts (121, 223); wherein the connecting passages for a solder contact (121, 223) to be checked runs from a respective measuring point to the reference potential via the solder contact (121, 223) to be checked in each case, via the respective internal diode and via the reference solder contact; - to determine reference information on the basis of the plurality of measured values to ascertain whether the reference solder contact has a defect or not; and - to ascertain on the basis of a plurality of measured values and taking account of the reference information whether one or more of the plurality of solder contacts (121, 223) have a defect. - a ball grid array, BGA, component arranged on a circuit board; wherein the BGA component comprises a reference solder contact which is connected to a reference potential; wherein the BGA component comprises a plurality of solder contacts (121, 223); wherein the solder contacts (121, 223) are connected to the reference potential in each case via an internal diode of the BGA component and via the reference solder contact; and - a test apparatus for checking a solder contact (121, 223) of the BGA component; wherein the test apparatus is designed, - to determine a plurality of measured values of an electrical resistance of a corresponding plurality of connecting passages for the corresponding plurality of solder contacts (121, 223); wherein the connecting passages for a solder contact (121, 223) to be checked runs from a respective measuring point to the reference potential via the solder contact (121, 223) to be checked in each case, via the respective internal diode and via the reference solder contact; - to determine reference information on the basis of the plurality of measured values to ascertain whether the reference solder contact has a defect or not; and - to ascertain on the basis of a plurality of measured values and taking account of the reference information whether one or more of the plurality of solder contacts (121, 223) have a defect. - to determine a plurality of measured values of an electrical resistance of a corresponding plurality of connecting passages for the corresponding plurality of solder contacts (121, 223); wherein the connecting passages for a solder contact (121, 223) to be checked runs from a respective measuring point to the reference potential via the solder contact (121, 223) to be checked in each case, via the respective internal diode and via the reference solder contact; - to determine reference information on the basis of the plurality of measured values to ascertain whether the reference solder contact has a defect or not; and - to ascertain on the basis of a plurality of measured values and taking account of the reference information whether one or more of the plurality of solder contacts (121, 223) have a defect.