S88 Keyboard. Pressing 1 black key also presses down two white keys next to it.

From the lowest B flat black note an on, pressing a black note also presses down the white notes next to it. I cannot play the notes individually. This is physically happening on the keyboard. Even when the keyboard is off, all of these keys act this way. How do I fix this so that I can play these black keys without playing the white keys next to them?

 

It needs to be repaired. That is a mechanical fault unrelated to power or software. You can try blowing some compressed air in there in case pet hair or cup o noodles dropped into keys.

 

If you haven't already, please get in touch through this typeform: https://bit.ly/NISupport_Hardware

 

May not work but I had a couple of keys knocked out of wack and this fixed them.
Push the front of the key or keys backwards gently.
Worth a try.

 

You saved my life jim. I knew it was something like this and not a defect. Thank you so much!

 

Pleased I could help. I just wonder if this is the cause of a few problems that other folks have been having with rattling keys etc.

 

Thought this maybe of interest, its a tear down video I found on you tube, I will be attempting this re-grease of the keys, once I find out what type of grease to use..

This guy had the same issue as you..