Do I need to replace a diaphragm?

[Bozo73]

New to forum and horn drivers, so I need some direction. Sorry for the length!
I recently purchased a pair of Altec 511b horns with drivers “from a VOTT” the numbers on the drivers are 33952 or 33953.
I tested the drivers with white noise from FM tuner off station. One driver was fine but the other popped and then performed similarly but at a subjective lower volume.
I took the driver apart to look at the diaphragm and there were dark spots where the leads attached to the diaphragm.
When I reinstalled the diaphragm and retested the first sound was a scratching/grating sound and then sounded normal.
Any thoughts? Thanks in advance for your consideration.
Bob

[Earl K]

You most likely just need a professional to look at your driver to get a proper assessment.

From the sounds of it, you have a rubbing voice coil within the gap ( BTW, the VC lead-ins are supposed to be coated in brown sticky goo ).

A pro ( with measurement equipment ) would widen the pin locating holes ( ever so slightly ) to allow for a smidge of movement ( then re-seat the diaphragm a few different ways while measuring to determine the diaphragm position that gives the lowest 3rd harmonic distortion ).

I'm pretty sure all that's ( currently ) beyond your ability .

:)

[Bozo73]

Thanks for the advice. Could the driver been damaged in shipment? Both drivers broke free of constraints and were banging against each other and the horns.
Any thoughts on how to find a professional with the right equipment? I’m located just south of Omaha Nebraska.

[robertg]

Great Plains Audio should be able to look at them. I've read good things about them.