alba ptv-10, radio sound ok, tv no sound or picture?

hi guys, i recently purchased a portable combi tv + radio, the model is alba ptv-10, for a few weeks it worked fine, but when i switched it on this morning, i couldnt get the tv to work. the sound and tuner for the radio is ok, but when i switch to tv, there is nothing (no sound or picture or even white noise). i am also having problems tracing a schematic for this product. I am not sure if its a faulty switch, capacitor or whatever and was hhoping for some helpful ideas/advice before i open it up....