Lcd samsung picture pulsats sometimes why?

Main system control memory IC fault. Contact any service technician to replace it. This is not a work, that a user can do with ease.
If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/

Sounds like a firmware corruption. Contact the authorized service centre for Mitsubishi. If you wish to get some details; check the site linked here. Viewing it in "Mosaic" will make surf easy.
http://electronicshelponline.blogspot.com/

analog board is most likely cause. Especially if you cant shut it off or change channels when it freezes.

I would say that the capacitors on the power supply board are ageing and changing value, stopping the start up system from working properly. Changing the capacitors may affect a cure.

Try manual tuning on that particular channel. if the transmission signal is week nothing can be done by the user.

called a TV repair store, got info over the phone for no charge and the TV is now as good as new. You should tell folks about the charge straight up, I wouldn't mind paying for a service but think you should advise at the onset.

is the picture clear when on? if yes, does the screen go black after a few seconds. if yes, sounds like you need a back light inverter!

Most manufacturers consider a few dud pixels to be normal and not a defect. Especially if not in the center of the picture.

Don't get fixated with watching the dot, look at the overall picture. It is like staring at a pimple on a pretty lady's chin.

easyab

as far as it turning off on its own I would get a fan on it and see if that make a difference make sure that the fan is able to flow around the tv especially through the back of it, if this stops it from turning off then it is an overheating problem

mamarabbit-It sounds like you have to autoprogram your tv channels,go into the menu and try to find setup or autoprog.Sometimes if your tv is unplugged for awhile,the plugged in it will automatically start autoprog.Try this out let me know how you make out. cooltek Mar.04/08