Do you have a MK I??
Do you know how to open up your MPC 60?
its just 4 screws Under the endcheeks, not the ones in them, the screws are in the metal below, not the plastic.
If you go the the roger Linn site the Downloads section (conviniently in the FAQ

) ther eare instructions PDF's for installing the 3.10 and SCSI which include disasembly instructions (highly underrated in many service manuals) with pictures for both MPC 60 and 60 Mk II.
The ram has a screw on top (maybe two, I looked at mine today but I was working on buttons) that you have to unscrew then you can pull the memory board out straight up I believe.
Shouldn't take you too long at all. make sure you unplug it before you do anything, once you pop the board out, close it up without screws and carefully plug it in and test 16 levels. if it works, shut down and unplug again and clean and reinstall the memory, close without screws again and test 16 levels.
Other things that can mess with your shyt like that is if you play midi data (tap the pads or midi keys ) while the sounds and PGM are loading, not a good idea and I have had sounds that get that without 16 levels when I've tappes the pads a whole bunch while loading.
If it works we'll put this in the faq.