Mk 2 knob slippage

My backup empeg finally succumbed to knob slippage. Had a quick look at the faq and previous comments and was thinking of just adding a couple of epoxy resin flanges to the shaft - very fine, but thinking that would be enough to stop the slippage.

Seems to me it should work, and is quicker than replacing the knob, but any gotchas anyone knows of that I should watch out for?

Is it a Mk2 or a Mk2a? In this case, I'm asking if you have the completely round stem or one that has a segment cut out of it?

Now, what kind of knob do you have? There were three styles: the original had a hub that was larger than the stem and had fine vanes that connected it to the stem; the replacement had a hub that narrowed to the diameter of the stem and used a small O-ring to make the mechanical connection; the third had a hub that was keyed to fit the segmented stem.

I almost immediately had problems with the original one. Replacements were mailed out for free, and I have never had a problem with it at all. Or the black Greenlights replacement buttons I got.

Anyway, what I'm getting at is that the correct solution is to replace the knob, and adding material to the stem might prevent you from using the correct solution in the future. (I don't know how hard it would be to get that epoxy off.)

If I were you, I'd modify the knob before I modified the stem. Assuming you have the original knob, it should be pretty easy to find a rod with the same diameter as the volume control shaft. Put that in there, fill up the hub partway with epoxy, let it set, trim off the rest of the vanes, and then put it back on with an O-ring. Make sure you have some sort of release agent on the forming rod: vaseline, maybe?

A tiny strip of thin, transparent office tape ought to do the trick.

Cheers

The gotcha would be if the glue was not dry before you put the knob on it. Then you would never be able to pull it off again.

Also, even if the glue is dry and the epoxy isn't actually sticking to the knob, if your trick works too well and prevents you from pulling off the knob easily, then you could still damage the encoder when you try to pull the knob too hard.

Wonder if Blu-tack would work well enough?

Thanks guys - Just for the sake of reversibility I'll try the sticky tape solution first and see how it goes.

Rubber Cement would work too. (a SMALL amount) and would be removable.

Be careful!

-Ben

Anybody got a part number, just rather replace it.

Click the "buttons" link at the top of the page.

I wrapped a thin layer of double sided sticky tape round mine, stops slippage, holds it on, but still comes off when required.