2. The ring shaped, capacitive FlexPCB had detached from the foam pad (the adhesive strip inbetween was smeary and gooey than sticky, I assume from aging), and thus had shifted, no longer making proper contact with the skin around the right ear. I removed the gooey, aged adhesive and carefully reattached the FlexPCB to the foam pad using several superglue areas.

Note that the foam pad ring appears to have a bigger diameter than the FlexPCB ring and the silicone cup. To me it looks as if the foam pad gets compressed in X/Y direction when inserted into the silicone cup, which makes reattaching the FlexPCB with its fixed diameter a bit cumbersome (I'm pretty sure they must have used a jig for compressing the foam pad in the factory to attach the FlexPCB). I helped myself by cutting the transparent Kapton section of the FlexPCB to turn it into an open ring.

3. The missing capacitive skin contact (either from broken solder joint or shifted FlexPCB), actually stops the two touch buttons on the ear cups from working. So even if the headphones are on and temporarily working until they fall asleep, the touch buttons don’t respond because of the faulty capacitive wear sensor.

Solder joint might look OK, but actually isn’t!

Three things I observed with my Nuraphones:

1. While the solder joint looked like it wasn’t broken and the wire appeared to be still connected to the solder blob, it actually was only held by Kevlar core inside the copper wire. The surrounding copper threads had been torn off, which was impossible to see with the naked eye, due to the fact that the blob was partially covered with copper rust AKA verdigris.Unfortunately I forgot to take a before picture, but here you can see the Kevlar and the verdigris:

https://live.staticflickr.com/65535/5344...

https://live.staticflickr.com/65535/5344...

In other words: Insufficient contact although looking OK on visual inspection.

„It should be the right cup.“ ... that should be in bold, red letters. The sensor is definitely in the right cup. There is no sensor in the left cup, so no need to open the left cup and potentially risking to accidentally tear off the extremely delicate audio wiring.