I have some wireless Sennheiser headphones that I use to listen to TV/BD which I connect through a surround sound amp.
Today I found I cant switch the headphones on at all But the 'unit' (the thing they rest on) is fine. The headphones dont seem to want to charge up either.
The manual suggests (among other things) replacing the batteries but if that was the issue they would charge properly. I dont want to have to buy new headphones

Have you replaced the batteries? If the batteries have reached the end of their useful life then they will not charge up again. Often you find as they age that you have to recharge them more often as you get less usage per charge out of them.

^ This

Ah good point, thank you I havent replaced the batteries yet, but wondered if it could be those I looked in the manual under 'No Sound' and it seems dead batteries could be a cause but I wanted to be sure.

Slight update on this - I bought some new batteries and popped them in, but still wasnt getting sound The unit is charging now though, so maybe I have to charge them before use
ETA: Everythings OK now, I hadnt noticed I had to turn the headphones up too so theyd work