We have had this tv for 5 yrs. It seems the brightness is getting darker and darker no matter how much we turn the brightness up. Sometimes it is difficult to make out the picture if the filming is at night time. Please help. Our tv is a 50" hdready 3LCD.

one of the components
chip or circuit board has failed

if you cant source that part

time for a replacement

Fault to its main board. Short circuited component/s at it. Contact any service technician; or the authorized service center. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/ . In most cases, the main board might have to be replaced. If so, a software [firmware] update too might be necessary.

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement.

How long u have this RCA analoge tv?Around 10 years or more and used it like about 5 or 6 hrs everydays?Yes,than ur tv it is losing CRT tube radiation cohetion.As times go bye years in years out the tv CRT-(tv tube) radiation will slowly dying out,Tv actual pictures will lost some of it luster and it brightnesses to the tv auctual pictures.Brightnesses of CRT tube will get darker and darker until the tv actual pictures barely it is watchable anymore.Contrast,Brightness and Colors adjusting more will help some.But u have to take this tv aparts and take a Flat scerw driver turn up a little bit more of the tv HV-(high voltage) SCREEN button on the FBT-(flyback transformer) to make any big differences of the CRT tube brightnesses.The FBT-(flyback tranformer) is the big block of plastic with a red wire with a black cap hook up to the tv CRT-(tv tube).This adjustment on of the FBT,HV-SCREEN button will help the tv CRT-(tv tube) last another year or two.

This is quite common actually I see it a lot. There really isn't any reason, it seems that when on batteries it trys to save power by Dimming Down, but it often just mucks up.. I always now set it via the keyboard keys. whenever I change from power adapter, to battery.

Try demagitizing the moniter. In the monitor's menu it will have a picture of a magnic , select it. Sometimes it is listed as degrous. After selecting this, your screen will seem to spin then settle. If your still have problems, a magnic may have come close to the moniter while it was being stored, and that will ruin the picture.

hi..first check it out the brightness.It is available in the
menu button,available on the top of the tv.If it still doesnt
work Projection TVs have a high intensity lamp as the light
source. They wear out and gradually get dim.You probably
need to replace it.
check it out..
thank u..
rate my response..

It could be your Light Engine. However, I would first check a few things:

1. Make sure your Low Power/Lamp settings are adjusted so that they meet your brightness needs.

2. Make sure you used a Mitsubishi original lamp, as generics get chewed through fast and hard.

3. Try another lamp; sometimes you can get a bad one in the bunch.

All those things don't work, consider a Light Engine ($400 + for parts; $300+ for labor)

Hitachi 46F510 different channels are different brightness and to get them viewable I have to run the brightness so high that you can not see any text at all. Also all white areas are blasting white bright. Edges of the tv also seem darker. I am connected to a cable system.

Caps in high voltage needs changing, needs tech