How to repair the magnetic on-off switch on the right earpiece?
I've had THREE of these headphones fail on me. The first was replaced by Sennheiser. The second pair now refuses to switch on though it charges OK. The third pair has started to switch off and on again randomly, which is the early sign of the problem.
The switch operates by rotating the right earpiece 90 degrees to a wearing position. I believe a tiny magnet in the headband causes a magnetic Reed switch to power the headphones on. For some reason, after a year or more, this becomes unreliable. I don't know if it's the fault of the magnet or the Reed switch but Sennheiser have refused to take ownership of the issue, despite the evidence that dozens, if not hundreds of users have experienced the same failure.
So ifixit, can you come up with a repair plan? These are expensive headphones (£200) and should not fail like this. “Please help me ifixit, you're my only hope!”