As of 2025, genuine Fanuc 10T main boards are becoming rare. However, the is still required if you upgrade to a retrofit control like Fanuc 0i-TF or Siemens 828D. Why? Because the retrofit technician must know the original parameters to configure the new drives.
Veteran service engineers often say: "The machine is just hardware. The parameters are the soul." The Fanuc 10T Parameter Manual is the only tool to recover that soul. Fanuc 10t Parameter Manual