As for Repair Stories, we had an accidental liquid spill into our K1 and much later it started to lose the velocity sensing on a wierd pattern of keys (for example 2 adjacent keys in each octave only played at full velocity). I had to disassemble the keyboard quite extensively to be able to use a mild solvent (teflon laced cleaner) to clean off the sticky conductive goo that had dried on the circuit board that holds the key switches. This is an exercise that requires patience, experience, and a steady hand. Do not open up your keyboard unless you are willing to suffer the possible negative consequences.
Now, we've also discovered that the keyboard has forgotten all it's patches (various sounds), and although they can be downloaded from a trusty Amiga, they get forgotten again after the keyboard is turned off for more than 5 minutes. We suspect the internal 3 volt lithium battery to be at fault, but stay tuned...it's soldered in without a replacable clip so some surgery will be required.
This just in, even with the lithum cell replaced, the keyboard still forgets patches when turned off. A mystery. None the less, it's still useful as long as you have a way to download patches along with you. It does cramp the use of the keyboard on trips.