Hi, folks. New to the forum, longtime recordist (first real gig at Sigma Sound Studios, 1970).
I love my old Sony MDR V600s, but finally abandoned them when the ear cushions crumbled again - the third set of pads I've put on them. Searching this time on ebay I also found and bought a replacement headband. While replacing the earpads is trivial, replacing the headband is not; it requires complete disassembly of one side or the other (I chose the right) to permit slipping the new cushion over the spring steel band and cable that connect the sides. It took me three hours, proceeding slowly to be sure I could put it back together again. That exercise left me with a better understanding of the engineering complexity of the things.
I also removed the foam plug in the center port of the drivers as suggested in old threads here. Mine, though, did not simply pull out; as happens in Florida, the foam had decomposed and turned to dust when touched, so I carefully scraped what I could with a small blade while avoiding the diaphragm. That, unfortunately, left small inaccessible chunks inside the driver - which buzzed with bass; I kicked myself for trying to remove the damned things - but I found a solution. While playing a heavy-bass tune loudly, I blew low-pressure air into the port at different angles; foam pieces, more than I thought could still be in there, popped out. No more buzzing bass!
The result is a pair of like-new 'phones, very satisfying.