 Posted: Fri Dec 09, 2005 6:40 pm Post subject: Red horizontal lines on sony KV X2993B |
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| Hi,
Argh, after swapping the cathodes, I still have red flyback, so my CRT is (almost) dead 
Maybe I will buy a new LCD set for xmas. Thx to all for your help and merry xmas. |
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| Posted: Tue Dec 06, 2005 10:46 pm Post subject: |
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| NO, SWAPPING THE INPUT TO THE CRT BASE WOULD NOT PROVE IT AS THE RGB DRIVES WOULD STILL BE CONNECTED TO THEIR CORRESPONDING GUNS, IT NEEDS TO BE THE CATHODE FEED RESISTORS. | |
| Posted: Tue Dec 06, 2005 9:40 pm Post subject: Red horizontal lines on sony KV X2993B |
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Thx Gary, as quick as light 
It would be easier for me to swap blue and red wires on the INPUT connector of CRT board : is it ok for you ? If the CRT would be used, could the image be OK for time to time (let's say 20s then several minutes KO, then OK again) ? Thx, once more. |
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| Posted: Tue Dec 06, 2005 9:27 pm Post subject: |
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| IF THE RED CATHODE VOLTAGE IS LOW THE PROBABLE CAUSE IS A U/S CRT, TO CHECK DISCONNECT ONE END OF THE RED CATHODE FEED RESISTOR AND ONE END OF THE BLUE CATHODE FEED RESISTOR, USE A WIRE TO LINK THE RED CATHODE FEED RESITOR TO THE BLUE CATHODE AND ANOTHER WIRE TO LINK THE BLUE FEED RESISTOR TO THE RED CATHODE, SO BLUE CIRCUIT NOW DRIVING THE RED AND VICE VERSA, IF YOU NOW STILL HAVE RED FLYBACK AND FLARING CRT NEEDS TO BE REPLACED. | |
| Posted: Tue Dec 06, 2005 9:08 pm Post subject: Red horizontal lines on sony KV X2993B |
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| Hello Gary,
I'm not sure to understand the real cause of my problem : suppose red signal on cathode is too low, what is the problem ? Thx for your reply. |
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| Posted: Tue Dec 06, 2005 1:16 am Post subject: |
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| JUDGING OFF THE FLARING YOU ALSO HAVE, I WOULD SAY THE CRT IS LOW EMMISION AND THAT THE AUTO GREY SCALE IS DRIVING THE CRT AS HARD AS POSSIBLE, MEASURE THE CATHODE VOLTAGES AND IF THE RED IS SIGNIFICANTLY LOWER THAT IS THE PROBLEM. I HAVE SEEN THIS ON SEVERAL OLDER SONY TVS IN THE PAST COUPLE OF YEARS | |
| Posted: Tue Dec 06, 2005 1:10 am Post subject: Red horizontal lines on sony KV X2993B |
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| Hello,
Thx for this advice. I can't see any 1000V voltage on the RGB board schema ? To test the driver / red gun can I swap the inputs (for instance red and blue) ? Thx in advance. |
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| Posted: Mon Dec 05, 2005 6:22 am Post subject: |
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| Too high screen voltage, or weak CRT. Set the Screen voltage on the CRT board. | |
| Posted: Mon Dec 05, 2005 5:44 am Post subject: |
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| first check dry solder on r\g\b drivers board that mounted on the crt neck. seconde you can measure the 1000 & 200 +dc lines on the same board.
if ok it seems to be an instant leakage between the grid & the cathode of the red gun |
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| Posted: Mon Dec 05, 2005 12:10 am Post subject: |
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| Did You check the Power Supply? (for example quality of voltage) | |