I just got the Fadal 1570-1 3 probe board and the list of fuses, relays and circuit breaker for the 1100-1 pcb.
I have a TS-27R tool length probe with MI8 and an MP12 with OMM and MI12,
The Fadal diagram does not show that the MI8 interface is used with the TS-27R probe, but I saw that you are using your MI8.
From where do you feed it 24VDC? Do you use the same 6 and 7 points on the 1570-1 as where the MI12 gets 24VDC?
Did you try to connect the tool lenght probe direct to the 1570-1 as per the Fadal drawing?
It looks like the 1570-1 board should have two ice cube relays, but my board came from Fadal VMC without relays.
If your board have them could you have a look for a part number, please?

All the best,

Andy