Small world
I have the K1r (since new) and a K4 which, with the help of Neil Johnson, I got upgraded to 1.4 ROM.
You are right - the K1 were 8 bit.
The K4 were 16 bit.
As for the sound, check the capacitor over the volume knob. There are some great references on the net - I think I added a post here too. What I did was to take a spare cap from my electronic bin, hold it over the tracks and hey-presto the volume of the K4 worked again. True mine was the other way around - with the cap broken it was full output but anyhow check this out.
If something worse has happened then too bad - however IF the aftertouch is working on the keyboard then console yourself you have a good action keyboard with a reasonable aftertouch - the K4 for example works beautifully with the EMU ESI and I believe you can zone the keyboard so you get to have more fun with the ESI.
I added some panels for Ctrl if you are interested for K1(r) and K4. One other chap improved on them but they can be found on Miniaktools site (my primitive version - Miniak Hacks! ) or check out the Ctrl website direct for modified versions.
Hope you get your keyboards fixed in time for Xmas.
Regards
Steve H