Project : Clavinova - where to go from here?

My attempt at repairing the Clavinova CVP-87A did not help (the audio output still sounds terrible), but there was a silver lining. It turns out that the MIDI out still works. I am currently using a Yamaha external MIDI sound module as the sound source. I disconnected the audio output of the mainboard, and connected the audio output of the MIDI module to the external input of the Clavinova. Unfortunately, there is no volume control of the external input -- the volume controls on the Clavinova do not work.

So, it is a perfectly good learning piano. I take my piano lessons on it. I love the way it plays. However, I can only control program changes. The first 10 are on their own buttons, the other 50 are available through more keystrokes. None of the other controls work, including the floppy disk interface. Every key has a corresponding LED, which is used to indicate the position of keyboard splits, among other things.

So my options are :

• Purchase a new mainboard for about $500, which leaves me with a Clavinova and its' 1993 era voicings. Next year it will be 20 years old.
• Do nothing and continue to use it as a piano controller with a bunch of non-functional controls. This is practical, but somehow dissapointing.
• Replace the electronics with something more modern. I have looked at commercially available MIDI controllers. Almost none of them provide for velocity sensing and very few provide for control of 88 keys.

I have thought of building a computer inside the Clavinova. There is plenty of space. I could probably salvage the amplifier boards, but not much else.