I enconuntered problem with one of CNC machine brand name Yang lather machine from Taiwan origin with Fanuc 0-i TB control.

When the machine has power up, an emergency alarm occurs which can't able be re-set, we found all signal in I/O diagnostic display page are missing. Button such as cycle start, feedhold etc has no signal in I/O diagnostic disply.

we have checked the flat cable connected from the I/O to operator panel which working OK, checked pin to pin and line to earth which is working OK.

we have decided to replaced the fanuc I/O board but after replacing the I/O board problem still exist. it could be the motherboard problem? or somewhere else?

Gents any idea?

Thanks,
Miles