EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: AutogolazzoJr on March 31, 2018, 01:04:02 am
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I have a kv-27fs100 flatscreen sdtv crt. I have had it since the beginning of time (built in 2002).
(http://i148.photobucket.com/albums/s27/1475233/20180330_204323_zpslix7dxv9.jpg)
There have been some issues regarding it.
(http://i148.photobucket.com/albums/s27/1475233/20180330_204531_zpsog6vdonc.jpg)
A geometry error seen towards the bottom.
(http://i148.photobucket.com/albums/s27/1475233/20180330_204355_zpsj98sq167.jpg)
(http://i148.photobucket.com/albums/s27/1475233/20180330_204403_zpsfu5ihyiq.jpg)
There is a convergence issue towards the top.
I have tried degaussing by unplugging, turning on and off, and repeating (I tried a few times). Anything else that can be done?
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What is the exact source and specs of the input signal and what other signal sources does it occur on?
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These were captured on two signals, one an intellivison flashback 240p composite, and the other component 480i ps2. Both had the same effects.
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I had one of these. This is the "funhouse mirror" effect. The dynamic convergence circuits required to keep the beam focused on a flat screen need to be tuned manually. You do this from the remote control with secret service codes.
Good luck finding them, I no longer have the TV or the information!
I think this is it:
http://www.neo-geo.com/forums/showthread.php?248996-Sony-WEGA-Trinitron-CRT-TV-service-menu-Tips-Tricks-and-settings-suggestions (http://www.neo-geo.com/forums/showthread.php?248996-Sony-WEGA-Trinitron-CRT-TV-service-menu-Tips-Tricks-and-settings-suggestions)
It was no fun adjusting this gigantic mess of interacting and mutually defeating adjustments.... :(
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I'd adjust the focus voltage first, and see if the screen voltages need adjusting.
I vaguely recall the convergence is dependent on electron velocity.
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I don't think you can adjust the convergence on most of the 27 inch models. It is supposed to just be pre-adjusted physically during assembly (maybe magnets?) and never require adjustment if everything else is working properly. Did this issue come on slowly over time or did it just suddenly appear without warning?
So, yes, I agree with the above suggestion to check voltages and check the operation of absolutely everything else first because otherwise it may actually be a physical tube problem.
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Most of these had rubber wedges between the yoke and the tube itself, on which the glue dried up or they shrank a bit with age - whatever. The result is the wedge(s) fall down to the board below and the yoke tilts slightly. If you can find them and re-insert them as they were, should clear up your problem.
Seems likely to me this is your problem.
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That looks similar to the effect you can get when capacitors in the vertical output section start to fail. Does the symptom improve as the TV warms up?