Printed circuit boards, or PCBs, also called circuit boards, are composed of microminiature electronics, including resistors, capacitors and integrated wiring. These circuit boards are found in practically every electronic device, including VCRs, DVDs, stereos, televisions, computers, stereos and cameras. If you are building a computer from scratch or attempting to repair an electronic device, you may have to test PCBs.
Inspect the PCB for visible flaws such as broken component connections or disjointed solder connections. Also, look over the entire board for corrosion or burn marks. Each is a sign that the PCB is not functioning.
Set a multimeter to test for "Ohms." Dial the multimeter to read the lowest resistance and hold the test probes apart. Look at the meter; it should read "infinite" or the highest level of resistance. Then touch the test probes together and the reading should be at or near zero.
Begin testing components on the PCB. Start with the largest components. Put the test probes to the component to see the resistance level; the higher the level, the more likely the component is not working. Components that read at or near infinity are not working. Test every component, marking the bad ones with fluorescent tape. Every component must be working for a PCB to function. If one component goes bad, the entire board will not work. Identify all failing components with the multimeter.
Unsolder the failing components with a solder gun, and solder new components in their place.