Click Here for various 16mm sound projectors, as I find stuff. Further links there to pages about specific makes, which cover both sound and silent machines
Click Here for various 16mm silent machines
Here is some advice on buying 2nd hand 16mm.
A thought that I have been pondering of late. Why are some16mm sound projectors so complicated, notably the Bell & Howell machines from the 620 onwards, but other machines too. Do they really need to be so heavily engineered and complex for the job they have to do? To the extent of needing special tools to do certain work on them?
Bear in mind also that 16mm was a very limited medium in professional terms. Picture was small, track was small, oddly compressed and with inevitably limited frequency range. It was just not capable of doing justice to all that engineering, nor were audiences sufficiently discerning to care - such small "improvements" as might be delivered would be lost on them. One wonders if it was a ploy to justify high prices?