Our LN40A630 has three horizontal white lines across the screen on power up (center, center of upper half , and center of lower half). After about five minutes the lines go away. Tried Picture Test in Self Diagnosis with no result.

Sound like your Y-Sustain board has one foot in the grave. The Y upper buffer and Y lower buffer boards go when the Y Sus Goes too...

Unplug it,then wait 10 minutes,then plug it back in.

According to what it indicates me it is a problem of screen what he says to me I suggest him to request technical assistance

Sounds like your TV is giving out, plain and simple.

If this doesn't sound right, then only one thing comes to mind. Have you moved the TV recently? Are you using a different coax cable, (if using cable that is). If so, just change the cable back to the previous one and you should be fine.

Across vertically or horizontally... It makes all the dif. It could be 3 boards on the set. The YSUS-main the YBU-upper/YBL-Lower. The Y buffer upper controls the top half of the screen, the Y buffer lower the lower half and the YSUS-main controls those 2 boards. They work in unison, when one goes they all fail. The other possibility is dry solder joints on the the D, G, E, F boards. All you would need to do with that is reheat the solder joints at the ribbon cable conx.

Best Regards and Semper Fi

Fixed non moving lines usually means you have a problem in the panel display or t-con. If it is in warranty get it to a factory authorized service center. If not you can try to change the t-con and see if this fixes the problem, if not then it will be the panel it's self and will be cost prohibitive to repair.

yes

if you can't expand your screen size from the pulldown menu or vertically or horizontally center the picture one or two of the centering coils could be partially burned out. the monitor uses electromagnets around the crt neck to center the picture. varying the center controls apply or take away voltage from the coils to center the image. may be time for a new monitor

sounds like a problem in the horizontal deflection circuit.possibly a solder problem. try re-soldering the horizontal transistor, line coils and yoke pins.

You have a vert sweep problem and unless you know how to trouble shoot this cuircit bring it to a pro. I found out mostly in these sets that the vert output IC is bad.. Also sometimes the b+ filter cap off the fly is leaky and made the IC to fail. Another thing is Im surprised to hear you got a pic with the vert failure and a bright line in the pic!! This could be a big problem when the sets fixed so dont run it too long like this. It could burn a line all the way across the screen and you will see a dark faint line in your pic because of this. BE CAREFULL!!