Disklavier

Merry Christmas to all,

Where is the sensor itself located?  What does the sensor do?  I have 
retraced my steps and double checked every connection... to no avail.  I also just 
discovered that I the sound generator is not working.  Piano plays perfect, but 
no MIDI tones... hmm.  The green LED on the small control box on the left 
front of the piano does not light.  I can't recall if it ever lit, but the on-off 
button on that box does not do anything now.   I cannot toggle from live to 
digital piano either.

I had carefully macro photographed all of the circuit boards and connection 
points as I had disassembled the "black box" I have now re- scoured over every 
connection.  All look tight.  I had carefully removed each connector without 
stressing any wire or it's respective pinch point within a connector.  I have 
to make the assumption that it must be something I have done or not done... 2 
variables in one equation is pretty rare.  Only other thought is that as the 
power supply quit, it took out another board or circuit.
Where does the green LED referenced above get it's voltage from?  That 
probably will be about 2.5v and I'd love to know if there's a test point for that.  
I have a wild guess that the missing voltage is also the reason the MIDI 
generator does not work.

Thanks again for everybody's help.     Jim