Dark and Granular Solder Joints on PCBs: Causes

1. Introduction Printed Circuit Boards (PCBs) are the backbone of modern electronics, and the quality of solder joints directly impacts their performance and reliability. Occasionally, PCB assemblers encounter dark or granular solder joints, which can indicate potential defects. These anomalies may arise from various factors, including poor soldering techniques, contamination, or material degradation. This article…