How messed up can one RDS CAA be?

[[Pe...]]

I am having issues with one of our RDS heads.  Basically at certain sequence of angle rotations it will cause the head to be so far off it is missing features, i.e. .040+inch.

I set up a 1-2-3 block on the machine and measured the corner of it with a plane on the top, front and side, starting at A90, B0, which I set as my zero point.  Then rotating the rds by increments on A, it will fail at certain ones.

 

 

It only seems to do it at arbitrary sequences.  Note that I have it going from A90, to A180 at the top (was running in "From characteristic list" order).  If I run that same program with A180 after A165, then that angle doesnt fail any more.

I have a ticket in with Zeiss for this since we had this issue before, but then when the tech arrived, I couldn't replicate it any more (I think IRC cal was done first thing before I could try to demonstrate it which may have fixed the issue for a time but now its back).  But I was wondering if anyone has seen a problem like this before.

[[Ri...]]

I had this happen to me. They were able to run a RDS check on it to confirm that there was an issue. They replaced the RDS. 

 

Mine was pretty severe though. At times you could visually see how far off it was, and then yes times it was off enough that either it crashed or gave crazy results.