Thin horizontal line across center of a black screen picture is restored when case is slapped several times.Panasonic model CT25G7F
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Anonymous
ANSWERS: 6
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There may be a cracked solder joint somewhere on the main circuit board, possibly the flyback transformer's connection to the circuit board, but look elsewhere too, since cracks on the flyback tranformer's connections would probably be more likely to cause a vertical line on a black screen.
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The horizontal line is a "collapse of field" and is usually caused by a dry solder joint, be very careful if you attempt a repair yourself (if you can find the suspect solder joint) because extremely high voltages are in certain areas of the circuit, especially in the line output stage.
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There may be a cracked solder joint on the main circuit board.
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This could also be the line output transformer (flyback) or the tran supply . Best bet if your not into repairs after resoldering is to take it in ...Amp
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Actually a horizontal line is caused by no "vertical" deflection. It could just be dirty pots in the vertical section. Work them back and forth a few times, will tend to clean them. There is normally 3, vertical size, vertical linearity, and vertical hold. It doesn't take a genius to get them adjusted back where they should be. Play with them.
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Dry solder joints on the pins of the vertical integrated circuit commonly causes this. Tap each I/C with a plastic screwdriver handle to find the intermittent one. It usually is one with a heat sink attached.
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