"Rebuilding" red trumpet horn?

[SKL1]

In putting my '72 targa back together one of the horns doesn't work- looks fine, took it apart but couldn't see anything obvious. Can they be rebuilt or any tricks?

[SKL1]

I've been corrected- this is a banjo horn- don't know how to edit the thread title!

[Solamar]

I just cleaned up and "tuned" a set of trumpet horns. Not sure if the banjos are the same, but their is a screw on the back of the diaphragm that tunes the sound. With power applied back the screw out till it stops honking, then turn it in till you get the tone you want.

Edit, I have no idea if this is a correct procedure, but worked for me.

[dicklague]

Originally Posted by Solamar

I just cleaned up and "tuned" a set of trumpet horns. Not sure if the banjos are the same, but their is a screw on the back of the diaphragm that tunes the sound. With power applied back the screw out till it stops honking, then turn it in till you get the tone you want.

Edit, I have no idea if this is a correct procedure, but worked for me.

I did the same about 19 years ago. One horn did not work and the other was just weak. Cleaned them up and adjusted the screw with 12vdc bench power. That was it.