Brightness problem, JVC AV-27230 27" TV

I have a JVC AV-27230 that of late has started to turn on rather bright, it goes down to less but still too bright later(unknow time , maybe 10-20 minutes or so). I have the brightness control set near minimum, same for picture slider on the on screen controls. When the set is initially turned on there are also a set(2) of dashed horizontal lines almost all the way across the very top of the screen, these vary in color from nearly white to a yellow green. These lines across the screen eventually settle down to two dashes single line in the upper left corner.

The high brightness is there when the TV is set to a blank input but the horizontal lines are not. A blank input is Video1 and I have nothing connected to that. Same high brightness when playing a dvd along with the horizontal lines, Video3 input.

After the "warm up" the horizontal lines shorten to two or three short segmented dashes and are only about one scan line thick, but not across the entire top of the screen. These line sit in the upper left corner and change colors from time to time. As I said I have the brightness slider almost all the way down, where it shouldn't have to be. I thought it was data coming from the cable but that is wrong if I have the same problem when looking at a different input.

With my crappy description does any one have any idea of where to look for what is going wrong with the set? A cap going bad maybe? I don't have a schem to this TV.

BTW, the sound is ok, it /may/ be getting louder but I am not positive on this. With that added it sounds like something in the power supply but I don't know what.

Ask if you need more or better info.

Thanks for any help.


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I got rid of the lines. I replaced caps 424 and 425, feeding power to an amp in the vertical section.

Next is to determine if the high brightness is actually in the set or if it is just the way cable has their channels setup. Some channels look just fine, some are on the dim side and others are rather bright. The cable company may have the analog channels out of order to get people to buy into the more expensive digital, it's a thought.

Thanks for the help, Thor

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Take a look at this thread:

formatting link

It tells you how to adjust the G2 voltage by changing the value in the flash and then re-writting the flash in the monitor. I got two Dell P991's fixed this way. 1st thing to check is if your monitor is on the list of monitors that will work with this method.


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Dan K

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