Here are the common methods to locate the identification number on a PCB:
- Check the silk - screen layer3: The serial number is often printed on the silk - screen layer of the PCB, which is the white lettering area used to label components and connections. It is usually near the corners or edges of the board. You can also look for text like "Serial No." or "S/N", and the serial number may be close to it.
- Look at stickers or labels3: Some circuit boards have a serial number on a sticker or label attached to them. The label is usually on the largest surface area of the board or in a consistent location across product lines. For example, the serial number label of consumer electronics and appliance circuit boards is often in an easily accessible position.
- Check the etched or stamped numbers3: Manufacturers may etch or stamp the serial number onto the bare circuit board material. This kind of identifier is durable but may be difficult to read. You may need to use a flashlight to illuminate the numbers stamped on the board and look carefully.
- Inspect hidden or obscured areas3: Sometimes, the serial number is printed in hidden places, such as under large IC chips or mounting plates. You may need to carefully move components or connectors to access these areas. In the case of laptops and other devices, the serial number on the circuit board is sometimes underneath the keyboard or on the underside of the mainboard. For folded flexible and rigid - flex circuit boards, check the bends as the serial numbers printed there can crack and separate when the board is unfolded.
- Use software to access serial number information1: In a professional repair facility, serial data communication programs can be used to access computer memory for serial number information. For example, in some automated test equipment, there is usually a subroutine that can fetch the unit serial number, identification, and modification status of CCAs, and even the identification of individual microcircuits.