Tower Type-3 ... shutter won't work @ 1/500

Hi,

I recently acquired a Tower Type-3 in great shape other than the 1/500 speed will not seem to work. I discovered this after the first test roll. The frames that are at 1/500 are not exposed except for a very small spot, thus no correct opening between the two curtains (?)

I have placed a piece of cut white paper in the film slot with the base off and eye tested the speeds. All look good enough except for 1/500. I double checked this method with my Leica IIIf and the paper insert is visible at 1/500, but not so on the Tower.

Are any adjustments possible, and if not, does anyone of a person for a possible CLA?

Thanks in advance for any input and have aa good day. Cheers, J