Casio CZ/ VZ/ FZ - Pro Series

Greetings CZ/VZers

I've been a lurker on this group for a while now, and
a CZ user for a _long_ time (I got my cz-101 new,
almost 20 years ago. I now own a CZ-1, VZ-1, and am
the former owner of a VZ-10m, and an FZ-10m (both
stolen from me) :(

Here's a problem I've had with my cz-1 for as long as
I've had the ear to hear it (since about '92 I'd
guess) 

midi data, coming out of my cz, makes clicking noises
on all the audio outputs, click-click every time I hit
a key (key down, key up) cliiiiiiiiiiiiiik when I use
aftertouch, the mod wheel, or the pitch bend wheel. I
haven't noticed this problem on my 101 or my VZ, only
on my cz-1... usually it doesn't bother me too much,
it's pretty quiet relative to the sounds I'm playing
typically, and if I'm playing live, I can turn midi
off and the problem disappears with it. 

has anyone else here experienced this problem?

Thanks.

Chris