Orion 80ED focus knob grips.

I went to use my 80ED last night and the grips fell off both focus
knobs! They were perished-looking and had both snapped.

My ED is mounted on an LX200 in a roll-off observatory. It can't be
heat (never gets hot) so I assume recent frosts must have done the
damage (despite having a frost heater)?

Pretty minor - but something to look out for. Anyone else had this
problem?

Cheers
Beats

PS. A couple of fat rubber bands are serving as ugly-but-effective
replacements...