Welcome to the world of the X-Y monitor, an electronic device that strikes terror into the heart of many a technician. The main reason it is so intimidating is that the Vector Beam, Quadrascan, or X-Y monitor is TOTALLY UNLIKE the Rasterscan monitor or T.V. set as you probably call it. Since many technicians are generally unfamiliar with the circuit operation, they may not be able to figure out when a symptom correlates with (points to) a particular circuit. If you are a technician, this section of the manual will certainly be a life-saver (our modest opinion). If you don't know anything about electronics, just relax because these monitors are a lot simpler than a regular monitor or T.V. set.
Vectorbeam or X-Y monitors are used because a regular Rasterscan monitor constructs the picture in a different way. For example, your T.V. set has 525 horizontal lines on the screen from top to bottom. Each line is a slice of the picture. If you stare real close at the edge of a picture of a curved object (a large ball) or an angular object (the peak of a roof) on the screen of your T.V., you will be able to see the individual slices that the objects edge is made up of. The edge of the curved or angular objects will not appear to be completely smooth but will look like they are stepped. However, at normal viewing distance, these same curved or angular lines will appear to be smooth or straight and not stepped. To make sure that the pieces or slices of the picture stay together just like they were transmitted, T.V. sets have syncronization circuits. Vectorbeam monitors don't use ANY of this. Here, the electron beam smoothly goes anywhere it is told to to paint the picture. It DOES NOT go across the screen 525 times to paint the picture in slices. Because of this shortcut, the circuitry is less complex and the detail in the figures will appear smoother. One drawback is that the brightness level is intentionally designed to be at a level high enough to burn or etch right into the picture tube face. This will be covered in more detail later in this section.
If your X-Y monitor develops a problem, you can go directly to the "SYMPTOM DIAGNOSIS" subsection where you can match up your problem to the problem described and the circuit that may be causing it. From there you go to the schematic diagrams for your particular brand of monitor and troubleshoot the circuits mentioned in the "SYMPTOM DIAGNOSIS" subsection.
If you are a technician who is unfamiliar with X-Y monitors, you may want to read the "THEORY OF OPERATION" subsection first. This section IS NOTa rigorous description of circuit operation, but a simplified general description of major circuit blocks. Some literature has been written on this subject. Electrohome's instruction and service manual on the G05-801 is an analysis on one X-Y monitor (which Midway Mfg. Co. does not use) described from an engineering standpoint. All that is necessary to understand it is a battery of U.N. interpreters. Electrohome's instruction and service manual on the G05-802 and G05-805 monitors (which Midway Mfg. Co. does use) is simpler and more condensed. The best manual we have found on the subject so far is Wells Gardner's publication oh their Graphic Display Unit, model 19V2000 (which Midway Mfg. Co. also uses). Most technicians will understand it and it is very complete. The above manuals are available on request from your distributor or monitor manufacturer.
For those who know nothing of electronics, we suggest that you read the "THEORY OF OPERATION" subsection, and we definitely recommend that you read the "TROUBLESHOOTING" subsection. From there, go to the "SYMPTOM DIAGNOSIS" subsection, and then to the schematic diagrams — the monitor's road map.
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