1 I wiggle my ears to adjust them

2 turn the left earcup into the off position

3 adjust the headband fit but only the left side.

4 sometimes just always on

It seems like when the pressure in that side changes it happens. I have opened it up and did not see anything obviously wrong, like bad soldering or worn wires. It makes me think that there is an issue with a mic in the earcup. I also think this because I have used it with only the left ear on but the right behind my ear so I can hear around me with and without the ANC on.

When I opened it up there was the main driver and then four paper covered things around it. They all looked good to me I can upload photos if it would help.

⟐ Commented March 08, 2025 at 14:56 MST

Story:

I have a pair of PXC-550 II (there's no page for the updated model, sorry). Due to my carelessness, I left them on for around 6 hours and they've completely drained the battery. I haven't done that with them yet. Then I tried to leave them on a charger for some while. When I returned, the sensor pad area was too warm, I can't really describe it as "hot", but it was like a laptop power brick in terms of temperature. There was no indication of charging. I removed them from the charger, and decided to disassemble them to find maybe the cause of heating up. After I've removed dynamic, I connected the power again to find what's heating up. It were, as far as I can tell, two ceramic capacitors. There were no visible heat damage or any kind of smell. That said, the indication appeared in form of red LED, with user's manual "less than 2% charge" that's deep discharge. Trying to push the battery out of that state generates more heat than during normal charging, but I couldn't tell if it wasn't too much heat. Although it did push out of that state, but 10 seconds after it stopped charging, either from protection kicking in, or, more likely, charging circuit breaking due to final failure of the charge controller. Still, there were no signs of burned electronics. I gave the headphones to a more knowledgeable and geared person in terms of board repair, but if you happen have some info on the right earpiece board (or just photos of both sides), it can help them (and me) greatly

Edit. I forgot to add, during all that time, the headset kept working on the "brains" level - it could turn on, connect to the devices, change the ANC modes, and sensor panel fully worked. But it soon always turned off due to low charge, even when connected with charger. I relatively know my problem, it's deeply dead battery that needs a "jump" (probably) and charging controller that's probably kicked the bucket. I need some sort of board images to locate and identify said charger so we can be sure that we can get the part and that painful board removal will bear fruit.

⟐ Answered November 16, 2023 at 23:48 MST

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!”

⟐ Commented May 19, 2022 at 19:20 MST

I wanted to use it, and realised one of the ear pieces wasn't making sounds. It's the right ear piece. I never connected it trough bluetooth to my laptop, so I was using the wire (the one that came with the headset) The wire goes in the right ear piece, if that matters.

I tried turning the headphones on and off. I connected the headphones trough bluetooth with my phone, still no sound from the right ear. I tried to reset my headphones next, witch didn't work either. I tested with another headphone both my laptop and phone, those work fine.

Does anyone know how to fix this?

⟐ Commented May 19, 2025 at 2:16 MST

If so, how many earpads is included in your listing?

⟐ Marked as duplicate October 17, 2023 at 21:42 MST