Over the past 25 years I have had the unique opportunity to talk directly with many of the professionals and instructors who use Overhead Projectors as an integral part of their profession. Through these interactions I have accumulated notes and information that has inspired me to write these articles that pertain to some of the most common problems experienced by owners of today's and yesterday's Overhead Projectors.

This is the third article in a series of articles that will be written from a professional Electronics Technicians point of view in regards to some of today's most common Overhead Projector problems.

A question that I am asked quite frequently is;