Following up on my earlier post, I managed to fix the MDR ZX 700s,
- Issue: exposed wiring connecting left driver to right driver inside headphone arm- I was incorrect earlier when I reported that power was flowing properly to the right driver (multimeter noob)
- Repair method: removed the damaged section of wire and soldered in undamaged wire (cannibalized from an inexpensive working headset)
- How long did this take: 8 hours for me. I had never soldered before and also reassembled the headset incorrectly multiple times
- Basic methodology: 1. confirm left driver is not dead (test ohms with multimeter, or better yet, desolder driver then test with a donor headset), 2. test left to right driver wiring by soldering known, good wire directly to the right driver from the left driver, 3. if step 2 suggest bad wiring, visually inspect for breaks, exposed copper, anything abnormal, then remove malfuncitoning section and splice new wire.
This was my first legitimate headphone repair. Overall, it was 'fun' but time consuming. Anyone who has a lot of time, a soldering iron, and is reasonably careful could do this. The ZX700 seems to be relatively straightforward to disassemble, but I still found it painstaking to reassemble.
The main advice I would give is to take lots of photos/video along the way so that you remember how everything goes back together. It would have saved me a lot of time to have good quality photos of the 'before' state.