Printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks. Using PCB chances of miswriting or short circuited wiring are minimized .The location of electronic parts is fixed and inspection time reduced. Defects in PCB are in the form like missing hole, breaking lines, wrong hole size etc. Image Enhancement Technique is used for PCB defect detection and classification of defects. The main goals in Image Enhancement Technique are achieving high performance or efficiency and obtaining highly accurate results. This is to ensure a high quality PCB that translates to reliable and quality digital end products. To enhance this work, we are going to propose a printed circuit board (PCB) is the board base for physically supporting and wiring the surface mounted and socket components in most electronics. This paper proposes a PCB defect detection and classification system. Image enhancement techniques have been widely used in many applications of image processing where the subjective quality of images is important for human interpretation. It is sub area of image processing.