I have a samsung ln55c630k1fxza sqv1 has audio ,but very dim picture what can it be

Switch on tv and go into menu, then check levels such as picture, brightness, if this is low change it to higher setting, it can happen if some one sat on the remote and caused setting to change. if this does not work with levels set to highest then there is some other issue with the led screen and needs checking by a technician.

I hope this was useful.