dynamic capsule repair

i have a Beyer M201 mic on which the diaphram has become unglued from the rim on the capsule body. This results in it having no tension to hold the diaphram clear of the body. Does anyone have any tips on how to re-glue it and tension it back up. I've had a go, trying to pull the diaphram out with sticky tape whilst the glue dries, but it didn't really work. Is this a lost cause?

> pull the diaphram out with sticky tape whilst the glue dries

That shouldn't be needed. Either there is a spacer-ring that has vanished, or the diaphragm is so badly warped that it will never work right.

there definitely isn't a spacer ring, so maybe it is warped. It certainly seems very soft. If i do pull it from opposing sides it does lift the diaphram clear of the body, but without tension it falls flat against the body of the magnet.

I've just had a look at one here - I think that these were probably externally tensioned when fitted, and then trimmed - I don't see how else they could be produced, and this is, after all, a normal method for tensioning diaphragms. Strikes me you either need a new capsule, or ask Beyer about a repair, because without something to pull, this seems futile.

If it's already in a poor state, then I suppose that you have nothing to lose by trying something like photo-mount glue, and sliding the edges out whilst it's still slippery. But this has got to be a bit hit-and-miss!