I’ve owned my Yamaha 9000 Pro for about 25 years. It was out of action for three of those because the internal power supply failed. One day I wondered whether another Yamaha model might use the same PSU, so I started searching online. I eventually discovered that the Tyros 1 uses an identical power supply to the 9000 Pro. I bought one, fitted it, and to my surprise it worked perfectly — and it’s been running flawlessly for the last three years.