Quote Originally Posted by jOHN
Back to the 288's.You should really work on fixing the locating dowel pins on those 288-8K's.As Pano & GM have said you need those to center the diaphragm easily and in a timely fashion.Once you have the pins you will make quick work of it before it drives you crazy or just takes too much of your time.. My point is it can become tedious.. But your doing a great job ! Keep up the great work Coen.

Fitting old drill bits in the holes and then cutting them to size is a great idea as GM posted.If not GPA should be able to provide them for you.
Sheesh AB,

The newer series 288s include a 2-piece dowel system ( which includes a hollow over-sized sleeve & a small bolt that holds that sleeve in place ) .

It is not, a solid metal pin that can be simply replaced by a small piece of metal rod ( cut to length and stuck in the threaded hole as you & GM suggest ) .

BTW, Pano is missing the 2 over-sized sleeves that are snugged-up inside the 2 locator holes within the diaphragm & held there by the set-screw . ( Look at the picture I posted of Panos open-backed driver to see the set-screws ) .

The center "hole" in the sleeve is larger than the diameter of set-screw, essentially allowing the sleeve to "float" or slop around a bit ( when the set-screw is loose ). This "play" when used in conjunction with the spider shim is what allows for an accurate fitup in the new system .

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Coen's description of what he has seen in his 288s suggests he might have a fully functional ( adjustable dowel ) system ( compare to the pic above ) .

He simply needs to read the instructions on how to use it ( along with the included spider shims coming from GPA ) .

DownLoad & Read ;Altec Lg-Format Driver Diaphragm Replacement Instructions