Vertical lines in the picture
This require you opening the television and having an ohmmeter to work with.
This is a vertical deflection problem - possibly a bad capacitor, bad connection, flyback/pumpup diode, or other component.
If the symptoms change - particularly if they become less severe - as the set warms up, a dried up electrolytic capacitor is most likely. If they get worse, it could be a bad semiconductor. Freeze spray or a heat gun may be useful in identifying the defective component.
It is often easiest to substitute a good capacitor for each electrolytic in the vertical output circuit. Look for bad connections (particularly to the deflection yoke), then consider replacing the vertical output IC or transistor(s).
A defective deflection yoke is also possible or in rare cases, a bad yoke damping resistor (e.g., 500 ohms, may be mounted on the yoke assembly itself).
Where there is a wide running vertically on the screen the likely causes could be a missing power supply voltage, defective vertical output IC, or a component associated with it is likely bad. A bad connection or blown fusable resistor may be the cause of a missing power supply voltage.
The following are NOT possible: CRT, flyback (except possibly where it's the source for a missing voltage but this is more likely just a bad solder connection at a flyback pin), tuner (except for the famous RCA/GE/Proscan or Sony models where the controller is at fault - see the sections on these specific brands). I am just trying to think of really expensive parts that cannot possibly be at fault :-).
Note that some movies or laser karaoke discs are recorded in 'letterbox' format which at first glance looks like a squashed vertical problem. However, the picture aspect ratio will be correct and turning up the brightness will reveal a perfectly normal raster above and below the picture.
May 20, 2010 |
LG 32LG40 32 in. LCD HDTV