DARK SCREEN My friend and I each purchased 21 in. flat screen Zeniths about 5 years. Picture on both has never been great, but it seems to be getting darker to the point where on some channels picture is almost blacked out. Changing settings does not seem to help.

sanyo is a junk tv, and I will NEVER purchase another....less than 5 years old black clouds on the screen, repairs are cost more than the cost of a new tv.....

If the brightness control is set to maximum and the picture is still too dark, two things might be happening. The CRT picture tube may have deteriorated over time, and/or the high voltage circuitry inside the monitor is failing to deliver enough HV to the tube.
In both cases theoretically it can be fixed (the CRT tube replaced with a new one, and the HV part cleaned of dust residue and repaired), but most probably it would cost not much less than purchasing a modern LCD monitor...

Lcd tv sets are lit by small glass florescent tubes called cold cathodes and, are powered by: ballasts called inverters... these go out just like your office florescent lighting the parts can be purchased online from electronic parts houses and, are easily replaced

well it looks to me u need a new tv....all the details u give are pointing that ur picture tube is gone.....but call LG help and costumer line and ask them......u may get away from it to get a new tv
make sure when u get a new plasma to extend ur warren tie to a max o 3 to 5 years and if this would happend u get it repaires for free.......cost for a new screen app 1000 to 1500 dollars

This is an indication of damage to the LCD panel itself. Unfortunately this can not be "repaired". The panle itself needs to be replaced. The replacement panel can easily cost almost as much as a replacement TV, so check around for pricing. You may want to try to locate another defective TV that has a good panel but electronic problems and swap the panel.

Dan

are you using the s-video input

Question when u loose picture do u loose sound also ? If so there is an 27Mhz xtal on the (SSB) small signal board that needs to be changed when it heats up it cycles out of phase. when it cools down it will work again till it heats up.

Hi there!
Have you checked for dust on the Tubes and mirror? This may cause a bad picture quality. Also power supply related problems like capacitors can cause a dark picture. Try replacing some of them in the power supply area and line stage.Also adjustments in the service mode,but for this you will need the service manual. Good Luck,JUS004

Does not seem like a bad tube alone. Could also be that the Video output Transistors Supply Filter capacitor having dried out. It is a 100mfd 160V capacitor, which on replacement will improve the brightness of the immage. And yes, you could also try increasing the heater voltage (Filament Voltage)of the Pictuire tube, this will definitely increase brightness, but will reduce the life of the Picture tube. You gotta think - 10 year old TV, should I repair or exchange and get a new one???