I tracked down an Oscilloscope and measured the MSA and LSA pins coming from the amplifier to the orientation board via pins 1,2, and 16 conveniently located right on the orientation board. From what I can tell by asking the Fanuc Rep what his interpretation of the readings were, is the amplifier has gone bad on the LSA line. I was only reading about 2V Peak Voltage and he said he remembers it needing to be near the 10V peak like MSA. Otherwise the shape generally looked good.
He thought the amplifier just wasn't amplifying enough for the orientation board to be picking it up. This would explain why I can see the LED's of the Orientation board light up every time the magnet goes by the sensor and why the spindle never locks in position.
The next step is to tear apart the amplifier and fix it because I can't justify spending the $675 for a used one or $1,400 for a new sensor and amplifier kit. I've started to tear into it and this is where I am at. They fill the whole thing with a rubber substance that makes cleaning it all out a pain. After a couple hours I got it cleaned up and now need to check part numbers and see if I can figure out the circuit, and what to actually replace....if not all of it.
Barch Designs
877-201-9771