Soldering Problems Printed Circuit Boards

Gideon Analytical Laboratories received four Printed Circuit Boards which had either opens or intermittent behavior on some of the P1 connector pins. A Printed Circuit Board (PCB)mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. PCBs can be single sided,double sided,or multi-layered. An open circuit is an incomplete electrical circuit in which no current flows. Gideon Analytical Laboratories was asked specifically if the soldering on the PCBs was problematic.

Failure analysis ensued to determine the cause of the opens, beginning with the solder joints. The PCBs were inspected using IPC-A-610, Rev E, and class 2 electronics standards. The connector pins were cross-sectioned to reveal any soldering problems. The first PCB had several questionable pins and a solder smear. The second PCB had solder balls, which violated section 5.2.7.1 of the standards which explicitly mandate that solder balls must be entrapped, encapsulated or attached such that they “cannot move”. These solder balls could move. The third PCB had a crack on pin 23 under the connector lead; this failed both sections 8.3.5.6 (fillet height) and 5.2.9 (fractured solder). Pin 39 on the same PCB essentially no fillet and a crack heal extending to the toe. On the fourth PCB, pin 21 showed the fillets improperly formed to the solder did not wet the lead. There was also a gap under the foot. Pin 23 on the same PCB not only had a crack, but the solder had not completely wetted the lead. Overall, there was no doubt that problems in the soldering process were the cause of the open and intermittent circuits on these PCBs.

Gideon Analytical Laboratories has time and time again exemplified both a broad and sophisticated understanding of electronics and nuanced set of problem-solving skills to help our clients. If there is a problem with any electrical component, Gideon Analytical Laboratories should be ground zero for the diagnostic process. It doesn’t matter whether the problem is in design, production, or the application. It doesn’t matter if the problem is in-house or a third party vendor, Gideon Analytical Laboratories solves problems. If you are having a problem with electronics, give Gideon Analytical Laboratories a call.

Solder smear

Solder smear

crack under the connector lead

crack under the connector lead

gap under the foot

gap under the foot

mobile solder balls

mobile solder balls

solder had not completely wetted the lead

solder had not completely wetted the lead