Help with Northstar Transport?

I own a Northstar transport that has stopped working. It uses the Phillips PRO-2 mechanism which I have read is very reliable and rugged. The transport has always worked great, but the other day a cd dropped out for about a half a second twice on the first song, but the rest of the cd played fine. When I put on another cd later that day it read "no disc". I tried several other discs and got the same "no disc" reading. If I unplug the transport and plug it in a few minutes later the track list displays in the window. The first song will play for about 20 seconds and then it stops. When I hit play again it reads "no disc". Any ideas, before I send it away for repair? Does anyone know if the PRO 2 mechansim is easy to replace?