JVC 27" AV27F803 Brightness fades to dark intermittently
My brightness or screen color dilemma is different than those posted. After viewing the tv for a short time, the screen will immediately turn dark. It doesn't slowly fade to this condition, but goes from normal brightness to dark rather quickly.
satellite (dish network)
Components not used full time:
Monster Power Center HTS 3500
Denon Receiver AVR 3805
TV is not directly hooked up to either the Power center or the receiver. It has an Independent outlet.
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Re: JVC 27" AV27F803 Brightness fades to dark...
I likely you have a loose conection in the crt board at the neck of the picture tube or a loose conection close to the high voltage transformer,I would suggest to tap the main board as well as the crt board with a wooden or rubber handle(not metal),be attentive were you tap to see if the set reacts ,if the set reacts you will need to resolder those places ,be carefull working on a set that is on while you do it,this should give some idea what the problem could be in case you want to call someone to help you with the repair.Let Us know if you need more information.
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I have the AV-27S33 model and in the rear to the right of the inputs are two slits and inside these slits are two screws. The top screw is the focus,the bottom the brightness.Your tv is a different model but it may have this same adjustment,if it does try turning the bottom screw to the right to increase the brightness.
There are two small holes on the rear side through which you can adjust focus and screen. Use a flash light and locate the two adjustable slots inside the holes. This part carries high voltage. Do not use a metal screwdriver to adjust. Put the TV facing a mirror so you can see how it works. Do not turn more than 1/8th of a turn. The focus control makes picture sharp or fuzzy. Screen control could change brightness. While watching the picture in the mirror, slightly adjust the screen control. Do not turn too much. If it doesn't work, then call a JVC authorized repair center.
Roger, if your contrast (sometimes called picture) and brightness controls are at max you can increase the tubes brightness by turning the "screen control" clockwise, be advised a little turn goes a long ways, don`t crank it too far or you will get retrace lines, you will have to remove the back from the set and follow the red wire down from the tube to the "flyback transformer" on the front of the flyback are 2 controls, focus and screen, do not move the focus control, this should fix your problem.
The picture is very dark
it is mostly due to
1 power supply output is low.
2 voltage on crt g2 pin is low.
3 video output supply is low.
4 some components in luminance section might be defective or loose.
5 finally crt getting weak is set is old.
If you feel good about opening your set then you can try this: Look for the flyback (high voltage) transformer, with the thick red wire which goes to the top of the picture tube. There are 2 controls on the flyback transformer, focus (top) and screen (bottom)Turn the brightness and contrast all the way down and then increase the screen control until you see retrace lines, and then back it down until those lines just vanish. Return the brightness and contrast to normal and adjust the focus control, if necessary, for a nice sharp picture. Let me know if that brings your brightness back.
This sudden changes in brightness are caused by the change in voltage inside the tv,not in the outlet in the wall but inside the set,The changes are an indication something is going wrong and it needs to be corrected,the set does have a brightness limiter but it only works when the set wants to get brighter than normal,You need the assitance of a servicer to correct this problem.