A vertical line apear on a tv screen and the sound is good . this product is sony tv model kv-21gmr

SOURCE: Black Screen with vertical lines down the side?

· http://esupport.sony.com/perl/news-item.pl?news_id=24
· Which models are affected with the "flicker" problem?
A1: There are 12 models in total: KDP57XBR2, KDP65XBR2, KP46WT500, KP51HW40, KP51WS500, KP57HW40, KP57WS500, KP57WV600, KP57WV700, KP65WS500, KP65WV600 and KP65WV700.

SOURCE: Standby indicator light on TV flashes - Sony TV

Hi,
    Please check fisrst that indicator liight (LED) blinks how many times.it could be from 1 to 8 times and the interval would be of three seconds.So, count the led flashes how many times and then tell me i will try my best to find and fix the solution.

Thanks 

SOURCE: Sony KF50WE610 Vertical Blue Lines Across Screen

the vertical blue lines indicate some interference from other electronic gadgets near your tv. it started showing up on my sony grand wega when i installed my wireless modem. i almost ordered a new rear projection lamp costing over $100 but decided to experiment. i first moved my desk computer farther away from the tv then isolated the wireless modem router by placing it inside a small glass - the vertical blue lines became lighter in color so i dedided to find another small glass that fit inside the first glass container then put the router in the double glass - no more blue lines and my wireless modem router still works.
do some deductive thinking to figure out what's messing up your tv and isolate the interference.
good luck!

SOURCE: Screen shakes / jumps vertically on my Sony KP-51HW40

The jitter is called a vertical sync problem. The problem is on the "A" board. It can be replaced or rebuilt but will be quite expensive to service.

michtech

SOURCE: Blue Vertical Lines on the screen

It means the optical block is going bad. Contact Sony support. They will sometimes warranty these even after the 1yr warrany has expired. Have your model and serial numbers handy.