Well, Paul was right. The new fuses burnt out right away when I swapped them into the unit. On the advice of KT tech support, I tried unplugging the ribbon cable connecting the front PCB to the rear connection PCB and turning the unit back on. That burnt out the same fuse.
Looks like something more serious is going on with this unit. I might be out of my depth here -- might be time to throw it on eBay and call it a day.