I have owned a Technics Digital Piano for 13 years and when someone inadvertently sat on the keys when the piano was on and demo music started playing. I have never heard this before and wonder how I get it to play demo piano music again?

Lots of advice on this page.

https://www.keytarhq.com/sustain-pedal-on-digital-piano-doesnt-work.html

https://www.google.com/search?q=technics+digital+piano+damper+pedal

..

Try these first:

https://www.justanswer.com/electronic-musical-instruments/axjnq-technics-sx-pr53-piano-sustain-pedal-will-sporadically-stop.html

http://www.mikebarden.com/technics-electronic-digital-kn-pr-px-piano-keyboard-ensemble-repairs/technics-spares-spare-parts/

https://ourpastimes.com/how-to-repair-a-technics-piano-12377949.html

technics-keyboards-forum

You should try resetting also called re-initallising your piano the instructions are in the manual. Here's a link-

http://technicskeyboards.com/technics-other/technics-manuals

Technics, digital piano, keyboard repairs, repair, service ...

www.mikebarden.com/technics-electronic-digital-kn-pr-px-piano-keybo...

technics, technic, tecnic, digital piano repair, service, servicing, digital, electronic, ... pr200, pr250, pr270, pr3, pr300, pr303, pr305, pr307, pr350, pr370, pr40, pr5, pr50, ... It needs extremely specialised repair work which must only be carried out by .... nodisplay, LEDS don't light up (except for the one on the front of the piano ...

I would suggest taking it into the nearest factory authorized repair center. Go to the Technics web site to find one in your area.

I don't see why Technics couldn't replace or fix it.

Usually you just select which demo BEFORE starting the demo.

If you are meaning to try to DOWNLOAD via MIDI or other those demo pieces that is USUALLY not possible as the pieces are stored in a ROM which is inaccessible via MIDI or USB.

They OFTEN don''t even send them out on the MIDI port when playing them.

If your piano is the same as mine, there is a rubber membrane with contacts imbedded in it that sits on top of a circuit board. The key pushes the contact in the membrane onto the contact causing a note on. What happens is the cylindrical part of the membrane that holds the contact can get torn and the contact will no longer travel in a straight line to trigger the note. The entire membrane strip has to be replaced. The strip on my piano was discontinued and I had to manufacture one from an extra Roland membrane that had some bad contacts in it. You will have to contact Technicsat www2.panasonic.com/webapp/wcs/stores/servlet/PNAEndecaSearchCmd for support. If you don't feel comfortable tackling the repair yourself consult a good piano tuner/repair place in your area for advice.