Just got my 168 back from Studio Maintainence Center in San Rafael, CA ( http://www.studio-maint.com ) where it underwent a Reset and self diagnostic cos it had frozen up on me and I  couldn't route any analog signals.

Turned out all it needed was the reset and it was fine. But when the tech explained how the reset was done, I realized it was similar to what I had done when I first tried to hook it up to  the computer; involving MIDI loops and certain buttons.

The reset also restores factory presets, FYI. It does not involve opening the case or shorting any pins. So if your unit locks up drop me a line and I'll send you a copy of the instructions.   I also would recommend SMC for repairs; they are an authorized Korg repair center, and now they have the service manual for the 168, thanks to me...

-cris in Sam Clam's Disco