The broken tabs and the tray-not-opening thing might be two different issues.

I have a prototype Central where the tray won't open when using the front-panel button. But if I use the remote control and go into the menu, and say "record from CD tray", "multiple CD mode", then it opens the tray.

The problem is that some of the front panel buttons have stopped working on that Central. Despite checking every contact and tracing continuity on every control line (even with a schematic obtained from Hugo himself), I was never able to solve the problem. I was forced to use that menu sequence each time I wanted to rip a CD.

So anyway, check to see if the tray will open when you use that menu sequence.