The process of designing and building printed circuit boards necessitates the use of various part numbers to ensure that a given electronic device can be repaired or replaced in the event of failure. As the boards are manufactured over months or years, the manufacturer may change parts or the entire design. In some cases, boards will have individual serial numbers to facilitate repairs and modifications. This traceability helps technicians see that the correct parts are installed.
Instructions
1 Look for the part number identifying the built up circuit board. In many cases, there will be two numbers printed on a board. One identifies the circuit board with an individual part number. The other part number will be for the board complete with all its components. Sometimes this is called a circuit card assembly (CCA) to distinguish it from the basic board without components. Near the CCA number, a serial number may be stamped with ink or handwritten. They're usually short, alphanumeric or hexadecimal numbers.
2 Look for a part number etched into a large wiring trace or a ground plane. These are solder-coated copper, sometimes with the manufacturer's logo, a CCA number, and perhaps a patent number cut out of the metal. Some serial numbers can be readily identified by the inclusion of "SN" or "S/N" next to a handwritten number. Some serial numbers can be found on small stickers affixed near the CCA part number. These sometimes have bar codes for both the part number and serial number.
3 Use a serial data communication program to access computer memory for serial number information. This means of extracting computer information is most likely to be found in a professional repair facility. In automated test equipment, this is usually a subroutine that fetches the unit serial number, identification and modification status for CCAs, and even identification for individual microcircuits. In WinViews, for example, entering "PS" on the command line will cause a computer to return its present status, including the serial number, modification status and more. Serial data communications programs are useful for these simple queries.
Tips & Warnings
Use magnification to read these part numbers and serial numbers. In some cases, it can be difficult to distinguish a 3 from an 8 or a 0 when the numbers are small and the ink is smudged.
Observe electro-static discharge precautions whenever handling circuit boards. ESD can cause degraded performance or destroy sensitive microcircuits.
