A TechLore "Ask the Experts" Question...
Question:
I have an old Mitsubishi (about 52+") big screen TV. It's connected to a wall outlet that can be turned on and off by a switch. In the past the TV has been fine with being turned off by the switch, but recently it was done and the TV somehow has dual colors, like one overlapping the other but they are offset. I've tried to turn it off and on to see if it would reset, but nothing. Could there be a feature that was pressed by mistake to change the view?
-submitted by ministone20
Answer:
Based on how you've described the problem, I doubt that it's any serious issue. It sounds like the TV's convergence settings were restored to the factory default, which would be way off by now. If you don't know what convergence is, here's a brief explanation.
Big screen TVs like yours use three large color tubes to create the TVs image. There's a red, blue, and green gun. When aligned properly these individual colors "converge" on the screen to make a full color picture. When not properly aligned, you'll see a problem like you're describing.
All TVs like yours have some user adjustable control for realigning the TV. Depending on the age of the set, you will find an option in the TVs menu (and realign the colors with the remote) or there will be a way to do it from the front controls on the TV (and you'll adjust little knobs on the TV). It's not difficult procedure; so don't worry that it will be tough.
Once you find the convergence controls, you'll see a large cross in the middle of the screen, several small crosses all over the screen, or a grid with selectable points (like the picture above) depending on the age of the TV. Each tube will draw the same cross, so technically there is a red, blue, and green cross. If you can see any part of an individual color, then the TV is not properly aligned. When each color is properly aligned there will be one cross that appears white.
Using the controls available, you need to adjust the individial colors to make the cross(es) white. You'll need to refer to the TV's manual for more specific instructions on how to do this. Normally, the green tube is locked, and you adjust the red and green tube to properly converge.
As mentioned above, some TVs have one cross, and others have many. If your TV has many crosses (or what appears to be a grid that you can select different points on) you'll be able to achieve better results than on a TV that only has a center cross. Do the best you can to make each adjustable point appear white. However, don't go too nuts if it isn't absolutely perfect...being off a little bit should be expected.
It's difficult to determine exactly what caused the convergence to reset. Although, turning the TV on and off with the light switch could be a culprit. Even though the TV has been fine up to this point, it's recommended that you plug the set into an outlet that always has power, and turn it on and off with the sets power button. Most electronic components use a small amount of electricity to store settings and other things when off. Besides, the constant unregulated power spikes from hitting the light switch can't be good for the power supply.
Matt Whitlock - Editor, TechLore.com
