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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Zenith Color TV Model # SR2568S Purity & Convergence Question
Highly suspect actually is the crt.
"Randy J. Evans" wrote in message om... Zenith Color TV R-Line Model # SR2568S Chassis # C10 The Purity is excellent, the Convergence is off only slightly, and shouldn't be noticeable to an untrained eye. The problem is the lower half of the picture has a green cast to it at times, especially when the camera goes from a fairly close up shot, to a camera shot that is pulled back, for a panoramic type view. If a camera shot has someone centered on the screen, from their neck down it has a green cast, the fleshtones from their neck up are not too bad, and near the top of the screen it will also take on a greenish cast. This set uses an LA7672 Jungle IC, and the Picture Tube is # A63AGD01X At times the picture looks perfect, although every few seconds, you can actually see the Tint change, like some type of Correction Circuit kicking in. I've seen this on a few other Zeniths, and it's a very annoying phenomena. So, using an NTSC Pattern Generator, Purity, and Convergence looks A-OK, but when actually receiving a broadcast signal, the problems present themselves. The B&W Tracking is good, as is Vertical Size, and Horizontal Width. I know my that my explanation of the problem is sketchy at best. Any Ideas appreciated ?? Thanks, Randy J. Evans |
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Zenith Color TV Model # SR2568S Purity & Convergence Question
Can your test gen put out a mid grey type of raster for testing? I have
a feeling that the mask in the CRT is defective, or the purity adjustment is out. If it cannot be adjusted out with the purity setup, it has to be the tube, from what I have experienced. -- Greetings, Jerry Greenberg GLG Technologies GLG ============================================== WebPage http://www.zoom-one.com Electronics http://www.zoom-one.com/electron.htm Instruments http://www.zoom-one.com/glgtech.htm ============================================== "Arthur Jernberg" wrote in message ... Highly suspect actually is the crt. "Randy J. Evans" wrote in message om... Zenith Color TV R-Line Model # SR2568S Chassis # C10 The Purity is excellent, the Convergence is off only slightly, and shouldn't be noticeable to an untrained eye. The problem is the lower half of the picture has a green cast to it at times, especially when the camera goes from a fairly close up shot, to a camera shot that is pulled back, for a panoramic type view. If a camera shot has someone centered on the screen, from their neck down it has a green cast, the fleshtones from their neck up are not too bad, and near the top of the screen it will also take on a greenish cast. This set uses an LA7672 Jungle IC, and the Picture Tube is # A63AGD01X At times the picture looks perfect, although every few seconds, you can actually see the Tint change, like some type of Correction Circuit kicking in. I've seen this on a few other Zeniths, and it's a very annoying phenomena. So, using an NTSC Pattern Generator, Purity, and Convergence looks A-OK, but when actually receiving a broadcast signal, the problems present themselves. The B&W Tracking is good, as is Vertical Size, and Horizontal Width. I know my that my explanation of the problem is sketchy at best. Any Ideas appreciated ?? Thanks, Randy J. Evans |
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