I have 2 sharp mini disk players - mt88 and an MT 180.
Both are suffering from the same fault.
Insert a disk, TOC is real, all looks ok but straight after HOLD is displayed. No end of button pushing in any sequence will get rid of this. Power off/open unit removes it, but as soon as you try again, same thing happens.

Lewis Randall, January 2006

You have locked your buttons so they cant be pressed in your pocket look for a switch to disable hold

Marko Kuszta, February 2006