Joseph,
I have the RAT assembly from a KDS20 I used as a donor machine. When first testing the KDS20 for operation, it wouldn't drain. Applying current directly to the drain solenoid got the machine to empty.
Further diagnosis was not pursued, as I never intended to install this machine. The timer might be to blame, but I have no way to be sure. You're welcome to it if you want to take a chance on it.
Ralph