Mellotronists

Hi Jerry,
I presume the fluon turnbuckles in these M400s are leftovers from 
M300 production...ie the ones that reputedly caused all the 
problems in that particular model. How do they work in an M400? 
Or was the problem caused by a combination of fluon turnbuckles 
and the narrower (more hence more wayward) 1/4" tapes?
John