Now mine's locked up too.  I was trying to send/receive midi when
it suddenly locked up.  Now no buttons respond.  I did the 'reset' procedure with midi cable to in
-&- out, went through every button test procedure, but no change when I power back on.  The logo
comes on, then the screen of whatever button I had pressed just before turning it off and back on.
Nothing responds.  No sound comes through.  Weird.