LC50UB30U Aquos Sharp TV Backlight Issue

Use coldspray to find the bad component abad soldering or a few bad capacitors in the (mains) powersupply . knock and bend the electric print some little the beginning is the powersupply


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If it is uneven, it is likely the backlight is failing.

does the backlight come on when you first power up the tv and then go out? This would indicate a backlight issue. There are usually several backlight inverters which all stop when one is broken depending on which one. You cannot check the voltage with a typical multimeter because it is very high, but you can disconnect one at a time until you get a display... it will be dim, but this will tell that it is a backlight issue and which inverter is the problem. It may be a CPU issue also... Honestly, for that tv, you're better off buying a new one. Repairing it isn't cheap or easy.

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It could be due to a bad inverter board or backlight.

This can be called Optical picture control and it adjust to suit the room light.

Please read the text below"

Dynamic Backlight Control - One of the nice features of the Sharp AQUOS LC-32D6U is what Sharp calls OPC, a name they use for their dynamic backlight control. You might also see this feature referred to as a dynamic iris on other LCD HDTVs or disguised under some proprietary name, but fundamentally the principle is the same. Its primary function is to try and maintain a high Full On/Off contrast measures the ratio of the light output of an all white image (full on) and the light output of an all black (full off) image. 2) ANSI contrast is measured with a pattern of 16 alternating black and white rectangles. The average light output from the white rectangles is divided by the average light output of the black rectangles to determine the ANSI contrast ratio. When comparing the contrast ratio of video devices make sure you are comparing the same type of contrast. Full On/Off contrast will always be a larger number than ANSI contrast for the same video device.">contrast ratio under any lighting condition. So when room lights come on or off or the sun enters the room, with OPC enabled, the backlight in the LCD will dim or brighten depending on the amount of light in the room. This is managed by a light sensor located on the front of the unit. When OPC is enabled there can be a slight reduction in the dynamic range of the display as the display attempts to maintain contrast and color saturation as room light changes. We had a chance to compare this feature with another LCD HDTV that was of comparable size but without dynamic backlight control, and the Sharp AQUOS LC-32D6U with OPC enabled was the clear preference.

It's either the backlight lamp or backlight inverter is busted due to a power failure or fluctuation. Here's how to determine which is which:

1. Grab a flashlight.
   
2. Turn on the TV.
3. Shine the flashlight onto the screen.
4. If you cannot see any display even a faint one, the backlight inverter is dead, else the backlight lamps are busted.
5. Replace which ever is the culprit.

first there could be many meanings of dims with a laptop screen one is backlight has turned off and it is difficult to see.  if that is the case use you brightness key to check if it is up, if it is more likely your inverter has gone up and in worse cases the screen. it may also start bright then change dim while loading
there is also the feature on mac to automatically dim the screen a little when unused for a set time.  to change this go to system preferences, go to energy saver, click show details, then move to options, and uncheck the the box that says "Automatically reduce the brightness of the display before display sleep".
i hope this is what you are talking about.

sounds like you have a bad panel. This ussually happens when a backlight lamp has gone bad and the inverter board senses this and sends a signal to turn the backlight off.