You should take your instrument to an Authorized Service Center.

Can you please give me contacts for Tanzania Yamaha service center please

Hello Ibrahim as regards the random selection on your Yamaha Motif XF8 Keyboard it's as a result of a bad Pnc motherboard. This motherboard can be replaced and installed in DIY.

Been a professional Piano & Keyboard technician for a decade now, I've come across over 50 of this Yamaha Motif selecting tones and programs randomly and perfectly repair them even without replacing the Pnc motherboard with a new one.

But I can help you get it in case you can't lay hands on any service centre in your location. Just give me a mail on chiemaftpiano.keyboardservices@gmail.com