Older television sets use CRT (cathode-ray tube) technology to produce onscreen images. Although CRT sets are usually reliable and can produce brilliant pictures, they have declined in popularity in recent years due to the availability of LCD and plasma sets. These newer sets are much less bulky and come in bigger screen sizes. Older CRT sets can suffer a range of problems including picture interference caused by magnetic energy and weak antenna signals. Serious technical problems usually require professional help, but many repairs can be undertaken without expertise