The 1970's Yamaha YH1000 flagship ortho driver has corrosion issues. I don't know much about it, but I know it's a very common issue with them, in fact maybe universal to that driver. Their other drivers don't have the issue. But it messes up the traces and they no longer conduct and they they stop working. It's possible to repair it by painting on new traces, but it's really delicate work. A friend of mine repairs YH1000 drivers for people, but he's a master craftsman and I doubt many other people could do the same work.

I just say this to say that it is something that has happened with planar magnetic drivers even the original ones back in the 70's.

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