Thanks for the thorough reply. That was spot on. I actually meant to follow up on this but I was finding this forum a bit difficult to use on android! What was baffling me was that the impedance were all checking out when I measured it and given the behavior of the headphones the fault had to...

Long time lurker here. I did this mod last night on a set that had been a bit hacked by someone else and I am finding that the sound is mono (i.e. left channel coming thru both speakers) I tested with a multi meter and there is no resistance (60 ohms) from the left circuit to the right...