My PSR-S950 became noisy after about 4 years of playing, so I asked a repairman to refill this grease. I had learnt about the grease long ago when I had this issue with another keyboard but never got around to do something about that. The repairman fixed the problem, but said, that a keybed itself is not designed for this procedure and after disassembling it for 3-4 times it can be broken.

I guess he used some usual grease, nothing specific, because, as he confessed, in his long practice he had never performed this procedure on such keyboards. Weighted keys, he said, are much easier to disassemble. Well, anyway, it became much less noisy, although, I think, slowly the noise is coming back, but I'm not going to play this instrument forever.

It is dissapointing that brand new SX do not behave like brand new items. I also recently read that users have to deal with a lot of problems with Korg PA1000 - something wrong with a touchscreen or with a keybed. Stops me from buying anything without a warranty. Also, stops me from buying things with warranty from semi-official dealers: they offer good deals, but you can't be sure if the warranty would be accepted as a legit. Yamaha keeps minimal prices rather high and doesn't care for those who sell these products for 20% cheaper. Obviously, official prices stop me from buying anything as well.

Usually companies, when they move/build their factories to countries where manpower is cheaper, chaim that it does not affect the quality at all. But today you can't even buy some LEGO for a kid being sure that it has all the parts inside. LEGO will send the missing pieces to you if you ask, but the fun is ruined anyway.

Well, it's true that today we buy much more of these things than we used to and manufactures have to optimise the process in order to prodive us all with products.

In the same time, I believe, when you expect people to work like machines, treating them as such, you should expect that something will go wrong after all.