![]() Check the capacitors that are near whatever function is not working properly (so if geometry is bad then check the caps that surround the deflection coil plug) If you have a schematic then you can use it to see exactly what capacitors effect the function you are having issues with.(Having the schematic will make this much easier.) If you see any capacitors that have blown up or otherwise failed catastrophically then it would be advisable to check the surrounding components that connect to the capacitor as one of them being bad could have caused the cap to fail. Start by doing a quick glance at all the circuit boards, if you see any clearly leaking or bulged capacitors then replace them and clean any potential leakage from the PCB.Here are some general steps for troubleshooting capacitors: Low quality or aging electrolytic capacitors are often to blame for issues with CRT displays. General geometry issues, one side of screen is too disproportionally sized or is generally not scanning properlyĪlthough a wide variety of things can cause such issues, one of the most common failures and causes of all sorts of issues in CRTs is capacitor failure. Many of these manuals and schematics are now available online, simply look up the model of your TV/monitor and look for a service manual.ĭescriptions and service manuals for Commodore monitors can be found here: Commodore monitors Repairs Symptom/Issue Here is a good guide to refer to for discharging CRTs: ĬRTs also contain mains voltage so general electrical safety precautions should be taken when working on them.ĭue to the facts that most CRTs come from a time when repair was more common and companies didn't claim it was a security risk to have someone replace a failed capacitor, complete service manuals that included full schematics were often given out to independent repair shops, in the cases of older televisions they may have even been included with the television. The tube MUST be discharged properly before performing any kind of internal repairs. Many times, they even throw away sets that often contain many useful components.CRT displays contain extremely high voltage (up to 30,000v!) and the acts as a capacitor which can store a lethal charge for weeks after the display has been unplugged. This is an ideal situation for the television experimenter. ![]() Another important reason for the experimenter to consider using the CRT is that unlike mechanical scanners, which are generally limited to the format they wereĭesigned for, CRTs can be easily changed from one format to another, usually by the twist of a knob.īecause of the popularity of television over recent years, many varieties of CRTs and their accessories are available on the new and used market at reasonable prices. It has good image qualities, such as brightness, contrast, and resolution as well as long life. Another is that it is has a low cost for what it does. ![]() The first of which is that it can operate at extreme speeds. The cathode ray tube of today has many important advantages over the mechanical scanners. This suggests that the mechanical systems may have often been a model for the electronic versions. At some point, someone ( maybe Farnsworth first ) must have looked at an operating mechanical system and realized that the sweeps were in fact linear and they needed to do the same with CRTs. This caused shading problems in the image and synchronizing problems between the sweeps. In the 1920s when Farnsworth, Zworykin and the others that were working with CRTs, they were using sine wave sweeps, usually supplied by small motor generators. And for a long time, they did it better!įor Example: Except for the vibrating mirror systems, all of the rotating disc mechanical scanning techniques, produce linear sweeps or scans. The only problem with this comparison is that long before the CRTs could produce television images, the mechanical systems were out there doing it. ![]()
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