The NBM VMC is a bios replacement board that includes a virtual memory card.
The MV1B, MV1C, MV1A and MV1FZ normally do not have the ability to support a memory card. This board tricks these systems into thinking there is a memory card installed.
In order to install this, you must completely remove or disable the onboard bios from your MVS motherboard.
The MV1B and MV1C are surface mounted chips and are a little harder to disable.
MV1FZ Instructions: HERE
YouTube Install Video: HERE