Sonoradude wrote:Thanks. Just sent him a message. Indeed, the diaphragm is loose. Is this an easy fix?
If you have steady hands and good close-up vision, it's not too hard. When rebuilding any sound box, it helps to have a spare replacement diaphragm of the correct size handy, since the fragile, original mica diaphragm is often damaged during the repair process and will have to be replaced. The diaphragm and gaskets can be ordered from any well stocked phonograph repair shop. In addition to the name I provided above, you can find many more by doing a search for Victrola Repair or Antique Phonograph Repair.
There were a couple of different types of sound boxes used by Sonora over the years. If it's like the one on this page --
http://www.phonographs.org/store/produc ... ts_id=1593 -- then it has a one-piece shell. In that case you'd:
1 -- remove the sound box from the tonearm
2 -- insert a tiny screw driver into the throat (back opening) of the sound box and turn the screw connected to the center of the back of the diaphragm counter-clockwise to remove it.
3 -- gently pull the needle bar forward to make sure it is not stuck to the center of the diaphragm. If it is, apply a little denatured alcohol to the center to melt away the wax or shellac holding it in place.
4 -- with a small screwdriver, gently nudge the front hardened gasket, working gradually, until you can nudge it out. The diaphragm should just clear the opening. Then, remove the back gasket, if it wasn't hopelessly stuck to the diaphragm.
5 -- clean all of the areas with WD-40.
To reassemble the sound box, simply reverse the steps above --
1 -- insert the back gasket
2 -- place the diaphragm over the back gasket
3 -- carefully nudge the front gasket in place, between the diaphragm and rim of the shell.
4 -- reinstall the tiny screw to hold the diaphragm to the needle bar
5 -- put a tiny drop of shellac or melted wax onto the front of the needle bar to seal the area.
For optimum performance the sound box should be completely air tight.
You can adjust the tone, eliminate buzzing or rattling, etc., by adjusting the screws holding the need bar's pivot in place.
If this all seems a bit much, most qualified repair shops will do a sound box rebuild for about $30-50, including parts.
HTH,
JDS