What characterizes a major defect in soldering according to J-STD-001?

A major defect in soldering, as defined by J-STD-001, is characterized by its impact on the performance of the assembly. This means that the defect can compromise the reliability, functionality, and overall effectiveness of the electronic assembly, potentially leading to failure in operation.

In the context of soldering, a major defect might include issues such as inadequate solder joints, such as insufficient wetting, voids, or cold solder joints. These types of flaws can hinder electrical connections, create resistance, or lead to intermittent connectivity, all of which can ultimately affect the performance and lifespan of the product.

Choosing the option that states it is a cosmetic issue only does not align with the definition of a major defect, as such issues might not impair the functionality of the assembly. Similarly, a defect being easily repairable doesn't pertain to its classification; rather, it is the defect's effect on performance that is critical. The idea that a major defect does not affect functionality contradicts the very essence of what constitutes a major defect according to the J-STD-001 standards. Thus, the emphasis on an impact to performance clearly identifies why this option is the correct choice.