Hi Thomas,
I grabbed a knob for my 710 back in the summer, and I've never been able to get it to stay on. Stayed on for 2 weeks when I first put it on, about a week the second time, couple of days on the next few attempts. I left it off at that point and forgot about it until recently since it's cold enough now that I'm wearing gloves, and remembered it the first time I tried to change volume with the original knob while wearing gloves. It seems like the hotter the weather, the longer it stayed on, and the more it went from hot during the day to cool at night, the more quickly it fell of