Fanuc 6T problem

[gridley51]

Fanuc 6T,on booting uo comes up with "slave ready" then goes to "bubble read" then after a few seconds goes to "not ready" in small letters.
No leds lit on main pcb,power supplies ok and checked at test pins on main pcb.
Have substituted bubble board and no change.
Am I looking at new main pcb or is there something else to check.

Mark.

On edit:I have a spare control but the main board is A16B-1000-0410 as opposed to the A16B-1000-0030 which I think is faulty.I have been told they are not compatible but is ther something else I could swap as well to allow me to use it.

[gridley51]

Have solved the problem.The spindle drive has a fault.Took the phases off the drive and shorted the fault relay and control boots up ok.
Big sigh of relief as prices quoted for exchange/repair motherboard were from $1800-9320.Still like an answer on the compatability question and does anyone have any info on BBC Veritron spindle drives.
Mark.