The PCB, or printed circuit board, is the heart of any electronics device. Components are attached to this board in different ways, though the most common is through the use of a BGA, or ball grid array. When components begin to fail it is important to know whether it is necessary to repair the PCB, or replace it altogether. Companies are utilizing state-of-the-art electronic inspection equipment to investigate PCBAs for faulty connections and installations. Simply identifying the problem is not enough, another important factor of repairing bad components on a board is the thermal cycle count. Too many thermal cycles can adversely affect the performance and integrity of the components on the board.
Before the need for board repair or replacement can be determined, it is necessary to perform a visual inspection of the unit. Electronic engineering firms have invested in a number of effective methods of looking for damaged areas or bad joints. The most popular of these is 3D X-Ray inspection and it is used to provide technicians with a perspective from the inside of the PCBA. These examinations are often expensive; therefore, many smaller companies employ specialized microscopes to offer a cost-effective solution to inspection.
In the instance that there is a faulty component discovered during the inspection, the choice to repair or replace the individual component is made. Each time a PCB undergoes reflow, or heating, it is counted as one thermal cycle. Excessive thermal cycles, numbering more than 3-4, are considered unreliable as the process deteriorates the structural integrity of pad adhesives, components, and the board material. When considering re-balling a BGA, it is vital to the success of the final product that the other parts of the PCB be able to withstand further thermal cycles.
Repairing or replacing a PCB is a decision that must be made carefully due to the possibility of causing further damage during testing. Excessive solder, for example, can cause unnecessary connections that can potentially make matters worse. The use of leading-edge technology and diagnostic equipment has led to effective and efficient testing, while understanding the effect of thermal cycles on the PCBA help to ensure a thorough repair or replacement.