I posted this question on Audiokarma as well. So far I have a recommendation to report the auction listing but no suggestions on the repair. I picked up a pair of headphones off Ebay. They are Realistic Pro II made by Koss around 1981 or so. The seller listed them as "new old stock". When I got them, I found one side had no sound. It's open circuit through the plug. The seller claims he checked them before shipping. I sent him pics of the ohmmeter reading but no further reply so far. I called Koss to ask about sending them for repair. They said if they have the Realistic brand, the warranty would have to come through Radio Shack. When I asked about paying for a repair rather than free under warranty, they said they don't do that. Just not getting anywhere on the phone with Koss. Continuity through the cable to the driver terminals is OK. The driver has a damper pad on the back held in place by a plastic screw plug. I took those off carefully and can see what looks like the back of the voice coil through four little holes. It doesn't look cooked. The driver is heat staked to the baffle plate, not screwed or bolted, so it would take some cutting to examine the dead driver any further, or to swap it out. But swap it out with what, anyway? I mean, if I can't get Koss to even check if the parts are still made...?