And since it does say repairs in the OP, I have actually taken apart two midi keyboards and a synthesizer. They all had non-responsive keys (likely spilled beer being the culprit). I wasn't keen on doing it to my $1800 (USD) Dave Smith Prophet, but their tech support guy directed my to instructions and a good repair video so I rolled the dice and gave it a try. To my amazement, I had no issues. With this newfound(land) confidence, I then proceeded to tear the housing off of two other boards and fix them as well.
With all the youtube videos out these days, it's a great time to be a DIY'er. Back in the pre-interweb days, it was a spooky proposition to attempt repairs or mods, going in completely cold. At least it was for me.