W7? Time travel might be the best way! Unfortunately, back then updates meant actually opening the keyboard and pulling out the old chips and replacing them with new chips. That kind of thing went the way of the cathode ray tube computer monitor, you just don’t see that kind of thing any more. Your best bet is to call your regional Yamaha office and ask if they might have an “old stuff” drawer with a set of W7 Chips... that would be your only hope... the seven year period to keep Parts after discontinuing has long passed, as the W-series was discontinued in the late 1990s.