How to check RRI Z2 Shim Power Supply Communication.

How to check RRI Z2 Shim Power Supply Communication RRI power supply is used on Twinspeed or LX with FMI 60642. It is a resistive shim power supply that provides only one channel; Z2. The same supply is used as the High Order Shim Power Supply where multiple channels are provided. The system must have a BRM coil (or TRM) with resistive coil windings built in. Ordinary LX systems don't have one. See Long Description. Can't get the RRI (Z2) Shim Supply to communicate. To test communications from the host, the “cu” command can be used from a Cshell window as follows: cu shimsupply [enter]. If there's no response, there are two pins on cable Run 1004 connector at the shim supply that can be shorted together such that whatever is typed into the "cu" window will echo back. This will verify that everything up to the shim supply is working.