- Inspect the surface of the PCB component body
If a used circuits board part has been polished to make it look new, there may be tiny scratch patterns on the surface when observed under a magnifier. If it is covered up with paint on the surface, it will look bright and have no plastic texture.
- Inspect the printed text
High-quality producers use laser printers to print the text silk-screen. It has a clear appearance, is non-conspicuous, and is difficult to erase. Typically, the text on refurbished chips is printed fuzzy and is not as sharp. You may find that the edges of the characters are blurred. The characters may be offset and the shades and colors may not be uniform. Moreover, many re-furbished chips use stencils for re-printing. In this case, if you feel the printed text, it should be easy to tell if it is new or refurbished.
- Inspect component pins
If the component pins are shiny with a thin coating, then it may be refurbished. Original components are tin plated, their color is dark, uniform and will not oxidize when scratched.
- Check the date code
The production code should be specific to a particular batch and should include the production time. If it is used, the new date label may be unclear or inconsistent with the timeline.
- Compare the thickness of the component body
Used parts are polished deeply to rid of old markings and make them appear new.
Therefore, the thickness will be significantly less than normal. If you compare them using calipers, it can be hard to distinguish if you lack experience. But if you look at the device at the front and inspect the shape, it may be more obvious. Since plastic housed devices are injection molded, the device edges will be rounded. But excessive grinding will reduce the plastic body to a rectangular shape with sharp edges, so these components must be refurbished.