9576C drive tray will not load type IV cartridge

The 9596C DVD-RAM drive will not load Type IV cartridge: I can remove the RAM media disk from the cartridge and place it in the tray and the drive will load OK and will read and write the DVD-RAM media. Any type IV cartridge will not load, the tray just closes and then opens again in 1-3 seconds. I need repair parts ordering information to fix this drive.