My 18 month old A350 is just now refusing to play some discs which it has played many times before. Some won't play, some have major drop outs. Other discs are perfect!!! The problem is with discs I've uesed before and new ones. Ronin and rob Roy are two long term discs which have been fine before The world at War I have had untold problems with. It seems to mainly be with gold discs. Has any one got any ideas about why this is or if it might be repairable?