Damn, that sucks so much. I got mine used from a fellow head fi member. Just arrived last night, I've gotten in touch with him as well. I googled a ton and nobody seemed to have any issues like mine apart from yourself. I don't have any experience with soldering unfortunately.
I failed to point out that my 'solution' doesn't involve opening the thing. (I wish I could open it btw - I made a mess of mine trying but bailed out before I broke it totally).
Yours may be something different, but mine entails setting it to balanced mode and using a working pair of the four channels coming out of the 2.5mm socket, along with a ground (earth) taken from the 3.5 for convenience. I just have to live with a short adapter cable with two plugs one end (plugged into the Opus natch) and a flying socket for my headphones. It still sounds fantastic to me, but the downside is I can't use the balanced out as I would love to. If I ever see another one at a price I can swallow, I'd buy it in a heartbeat !