Joint Contamination on a pcb electronic board

Figure 1: The lead-to-hole ratio here was excessive.

The top of the plated through hole in Figure 1 has been contaminated during the soldering operation. The temperature has caused the coating on the resistor network to soften and has contaminated the board surface. During pre heat the top board temperature would normally be 100-110°C and may well reach over 190°C when contacting the wave. The component should not have caused this problem if normal process conditions are maintained. The component should be reassessed for process compatibility.