Procedure for the manufacture of printed circuit boards with mixed components, on the first side of which at least one THT component and at least one SMD component (5, 7) are arranged, and on the second side of which at least one SMD component is arranged, wherein in said procedure - the SMD components to be arranged on the second side are secured on positions provided for this purpose on the second side of the printed circuit board, - the SMD components (5, 7) to be arranged on the first side are placed on contacts (17, 19) which are provided for their connection on the first side by inserting a solder (13, 15) having a low melting temperature (Ts), wherein the solder (13, 15) having the low melting temperature (Ts) has a melting temperature less than or equal to 210 °C, - the first side is equipped with the THT components to be arranged thereon and with the SMD components (5, 7) to the arranged thereon, - the equipped printed circuit board passes through a preheating unit during a predefined preheating interval (ΔT1), wherein the second side of the printed circuit board faces towards the preheating unit and a heating power and a duration of the preheating interval (ΔT1) are sized in such a way that a temperature on the first side is, at the end of the preheating interval (ΔT1), slightly greater than or equal to the melting temperature (Ts) of the solder (13, 15) for a solder period (ΔTL) which is long enough to melt the solder (13, 15) situated on the first side, such that the solder (13, 15) having the low melting temperature (Ts) is melted and the SMD components (5, 7) arranged on the first side are soldered, and after passing through the preheating unit - the SMD components situated on the second side and the solder points, situated on the second side, of the THT components arranged on the first side are soldered using a wave soldering process, wherein the second side of the printed circuit board faces towards a solder wave. - the SMD components to be arranged on the second side are secured on positions provided for this purpose on the second side of the printed circuit board, - the SMD components (5, 7) to be arranged on the first side are placed on contacts (17, 19) which are provided for their connection on the first side by inserting a solder (13, 15) having a low melting temperature (Ts), wherein the solder (13, 15) having the low melting temperature (Ts) has a melting temperature less than or equal to 210 °C, - the first side is equipped with the THT components to be arranged thereon and with the SMD components (5, 7) to the arranged thereon, - the equipped printed circuit board passes through a preheating unit during a predefined preheating interval (ΔT1), wherein the second side of the printed circuit board faces towards the preheating unit and a heating power and a duration of the preheating interval (ΔT1) are sized in such a way that a temperature on the first side is, at the end of the preheating interval (ΔT1), slightly greater than or equal to the melting temperature (Ts) of the solder (13, 15) for a solder period (ΔTL) which is long enough to melt the solder (13, 15) situated on the first side, such that the solder (13, 15) having the low melting temperature (Ts) is melted and the SMD components (5, 7) arranged on the first side are soldered, and after passing through the preheating unit - the SMD components situated on the second side and the solder points, situated on the second side, of the THT components arranged on the first side are soldered using a wave soldering process, wherein the second side of the printed circuit board faces towards a solder wave.