Need advice. Frozen flange in throat of brass Orth. SB

[unclebernal1929]

I have a very good brass Orthophonic Sound Box/Reproducer and the hardened rubber flange is frozen stuck in the throat of the reproducer. I also see the the taper-tube pin that is in the flange is not in line with the top set-screw causing the needle to be slightly steeper in angle to the record than recommended. I have removed the two set screws and I have tried to put it back on the taper tube and slightly force the seal to break where the hardened rubber meets the throat. Won't budge at all. I don't want to use THAT much force. Everything else seems good. Airtight and great bass response when playing on my two-door CREDENZA. Any advice on how I can get this hardened rubber flanged UN-frozen? Help!

[wtt11]

Yours has pot metal retaining ring. So as you said, don't try hard unless you remove the throat first.

[wjw]

I melt these out of No. 2 reproducers with a heat gun which works great but the reproducer is disassembled. If you dont want to brave unscrewing the back of the Orthophonic you can carefully pack the throat with aluminum foil (or a nice fitting wood dowel section) and dig the isolator out. I have done this with a jeweler screwdriver heated frequently with a torch. Didnt take long but the smell is awful. Make sure to mark the position of the flange pin. The angle looks correct to me. Hopefully an orthophonic whiz like Phonojim will post on this. Good luck with it-Bill

[briankeith]

Send it to Peter Wall.

[phonojim]

Bill, thanks for the compliment.
I have used a heat gun to remove these isolators. I think the originals were sealed in place with shellac rather than just set in place and held in with the setscrews. In your case, I agree with other posters in that you need to be very careful in your attempt to remove the isolator with the flange still attached to the reproducer. You could use a soldering iron with a narrow chisel tip that will fit down into the channel. I have used a Dremel with a burr to grind out the rubber. It works but is difficult to guide and tends to wander, so you want to keep it toward the inside brass tube. If you use this method, you must pack the center with cloth, paper towel, etc. to keep fragments from getting into the reproducer.
I use shellac to seal a new isolator in place, or if it is a loose fit, a little bit of black RTV. Just be sure that it is positioned correctly before applying adhesive! Once you have it in place, reinstall the setscrews carefully so that everything stays in place and let it sit for at least 24 hours so the adhesive will be cured before you put it back on the arm.
A note on isolators: the last ones I bought from Ron Sitko had ridges on the inside face to space the brass tube away from the reproducer back. If your isolator doesn't have these, use an O ring of 1/16" maximum wall thickness, preferably less with an outer diameter appropriate to the bore of the reproducer to space the brass part of the isolater away from the metal surface of the reproducer. When properly assembled, the locating pin in the isolator should line up with center of the upper setscrew hole. I checked my 8-30 for stylus angle and found that it is right around 60 degrees which I think is correct by Victor standards of the period. I used a ⅝” long steel needle with a Victor scroll record on the turntable.
I hope this long-winded post helps.
Jim

[howardpgh]

If the isolator ring is glued in with shellac, couldn't it be loosened with some alcohol applied with a syringe?

[De Soto Frank]

If the isolator ring is glued in with shellac, couldn't it be loosened with some alcohol applied with a syringe?

Yes, but have to apply sparingly so that it does not reach the backside of the diaphragm and melt the shellac that seals the spider to the diaphragm.

[De Soto Frank]

If it were mine, I think I would plug the bushing to prevent debris from getting to the the inside of reproducer, then carefully flatten-off the exposed end of the rubber bushing with a wide file or sandpaper on a flat surface, then begin carefully drilling-out the fossilized rubber using a fresh, sharp bit, that is not more than 75% the width of the rubber, marking a depth-stop on the bit with masking tape ( or setting-up in a drill-press, and setting the depth stop accordingly), and drilling holes in the rubber one next to the other, continuing around the bushing, leaving little webs in-between the holes.

When you've gone all the way around, then carefully remove the "webs" with tiny needle-nose pliers, or a sharp screw driver, then finally mount on a gooseneck, and twist the reproducer body carefully until the remnants of the bushing shear, and the body releases from the brass insert.

Then you can carefully clean-out the remaining rubber.

Unless you're going to disassemble the reproducer, and get the back-plate separated from everything else, I would be reluctant to put heat on it...

[JerryVan]

I don't see anything wrong with this. The angle looks right to me. If it plays as well as you say, I would leave it alone. Forcing it will only break off the locator pin.

[Player-Tone]

The angle looks right to me.

Me too. I measured 70 degrees from the picture, which is normal for an Orthophonic. If it were pre-Orthophonic than it would be too steep, since those are usually at 60 degrees.