Printed circuit board (PCB) assemblies are manufactured using an assortment of complex electrical components, including resistors, capacitors, diodes, transistors and relays, just to name a few. The functionality of any circuit board depends on each element performing and functioning at a specified level. If any component fails, the PCB assembly can experience faulty performance or the overall device may have a complete failure to perform. That is where Tim Jefferies, Test Engineer and 13 year team member of MJS Designs, comes in. As the lead of the test engineering team, Tim’s involvement in a project means that a customer is committed to reducing field failures of their product and wants to be fully informed of potential weaknesses in the functionality of their PCB. Tim’s focus is to make sure the customer is fully aware of the potential weaknesses in the functionality of their PCB assembly and to make recommendations for corrective action.
Testing in general is a flexible and customer driven process; the customer may opt to test the entire board or system or may opt to test specific parts or components.
The key benefits of testing are:
- Speed to market – When testing is integrated into development, test engineers like, Tim Jefferies at MJS Designs, offer standard risk avoidance strategies and mitigation best practices for the further development of an electronics project.
- Cost Savings – Reduces engineering debug time for issues the test will be able to identify.
There are a variety of functions Tim and his team are called upon to be involved in, and the functions include:
- Schematics review – to verify the accuracy and completeness of the PCB electrical information. This is the information that will be needed during troubleshooting efforts when test failures occur.
- Design for Test (DFT) – to add features to a board design to enhance its testability. Basic DFT features would include ensuring that pad and trace dimensions are sized to support flying probe and other automated testing. Adding test points, test connectors, and other test access for use by manual and automated test equipment is also part of a good DFT design. Other DFT features might include adding boundary scan test access ports and boundary scan connections on the board between components.
- Creation of functional test fixtures – to assure that the device under test is held in place and to allow it to be connected and subjected to controlled electronic test signals.
- Documentation – to assure the customer has a thorough and complete record of the test procedures, findings and corrective recommendations that are needed.
As a result of these efforts, the electronics manufacturer is able to pinpoint and identify problems such as out of tolerance components, incorrect resistance readings or shorts between power and ground. With decreased passive component sizes which prevent component markings, test ensures component vendors are supplying correct values. Schematic errors can be caught during test rather than during engineering debug.
Tim, who has a Bachelor’s Degree in Electrical Engineering Technology and is an alumni of ITT Technical Institute, was recruited by MJS Designs to help build out the testing services offered by the company. In addition to overseeing all test procedures in the company, Tim conducts the research and makes recommendations to bring in state-of-the-art equipment like SPEA 4060 dual sided flying probe system which MJS Designs installed in its Phoenix, Arizona headquarters in October 2013.
It is important to understand that not all flying probe testers are created equal. Different levels of test can be achieved by different equipment. Some flying probe testers are simply a pass/fail test. At MJS Designs, the flying probe test is as in depth as an ICT test. In fact, the same software is utilized for the SPEA’s ICT testers as their flying probe testers.
MJS Designs has a variety of Test Methodologies available that have different benefits which are outlined in the table below.
“There is a lot of satisfaction in being a test engineer. There are many times when a board goes through testing and we catch a number of failures that a visual inspection can’t see and thus would have been discovered in the hands of the end user. We prevented that loss of time, reputation and money for our customer with our testing processes,“ – Tim Jefferies.
The testing services at MJS Designs are customer driven and are included in RFQ’s, however, not all customers take advantage of the diverse testing services offered by MJS Designs. Some customers have their own testing abilities in-house and some do not test until a project is completed.
Tim Jefferies and the team at MJS Designs are happy to discuss testing options for your next project. Live chat at www.mjsdesigns.com