This is on the TC-78 cassette deck. Has anyone else had a problem where the tape does not advance in a smooth manner when playing. Well it does this on mine. It also makes a loud whirring noise. I opened it up and found the drive cog to the take-up reel has worn down, particularly at the edge. I guess that at some point the other cog that meshes with it didn't engage fully and now doesn't engage very well at all. Curiously I looked at the B-side driving cog and that's looks as good as new although it appears to be made of a different material (orange coloured plastic), where this one is black plastic.