I have a LG CT-34M20ET that has a problem with focusing, blurring picture, I have played with the contrast, and flyback transformer adjustments, no differing in picture, any possible suggestions would be handy.(electronic technician I know TV's can bite)
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Re: TV focusing problem
It's good that you know how TV's can bite, I'll still have to post this in case someone having your problem and reading isn't aware of this and feels lucky-
If still under warranty or if you have no electronic repair experience you should take the set back to the shop or to a repair person. Some of the solutions described below can be dangerous, TV's are very hazardous to service. Even when plugged out, TV's can store very high voltages.
could be a problem with the screen potentiometers block. should be located on the chassis close to where the HT lead passes on its way to the picture tube.
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blurred picture can be adjusted,and sometimes replacing of crt socket will solve the problem.
this is tricky so i've advice you to follow what i've said strictly.
Open the back cover of your set (make sure that you unpluged the unit first).
Look for the flyback transformer (it has a sunction cup connected to the picture tube).
You will see an adjustment knob on it, it mark focus but wait before touching,mark it with your pentel pen,marking the original location of the knob is important because that is the factory align.
After marking get an screw driver w rubber insulator as a handle to avoid an electric shock,this will be used to adjust the focus on the flyback knob.
Turn on the unit and hooked it up by your dvd player.
Play the dvd so that you will see a picture on the screen.
Pause it with a picture with characters.
Now you can see the blurred picture?
Try to adjust the focus on the flyback back and forth minimal turn only.
There's a reaction?Yes- continue to get a perfect picture and youre done.
There's a reaction?No- back the knob on its original position.
Your crt socket is faulty.
try some helped of your technician or people knowledgeable of disoldering and soldering technique.
Pull the board on the crt socket.the socket which attached to the tube is the one you are going to replaced. I've adviced you to observe first and familiarized what are going to dis-assemble because you will do the same when you replaced a new one.
After replacing your crt socket,picture ok?Yes-you're done
After replacing your crt socket,picture ok?no-picture tube is faulty.........
This problem requires adjusting the Focus on the flyback . Turn the tv around and look for adjustmen slots on the back. If you can see them, use a nonmetalic small srewdriver and slighty adjust the top or left one. Be careful, it is the high voltage area
you can take the back off find your flyback (the big part with a red or pink wire going to the picture tube) and adjust the small pot or potentiometer closest to the top while the set is on in front of a mirror and try adusting the focus control.
if cant get nothing but blur replace the fly or focus assembly if not built in the fly. I would change both.
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.
When you replaced the flyback the new flyback is shipped with the screen and focus controls set at minimum. These are the 2 controls on the flyback itself. Turn the set on and let it warm up a minute, then slowly turn up the screen (bottom) control with a small flat-head screwdriver. When the picture is around normal brightness, adjust the focus (top) control until the picture is nice and sharp. Then, turn the brightness and contrast all the way down and set the screen control until you can just see the picture, just above the point where the picture vanishes. Reset the brightness and contrast settings and your picture will be back to perfect.
Well you did start out good, thats cool, now we have to define focus, Is ir blurry around the edges as well as the whole Picture? If it is, it could be the picture tube, A bad solder connection on the tube socket, and yes it could also be the flyback transformer.