Disable LED "screensaver" on TR-08/8S/09/TB-03?

[Architekt]

I know how to turn off demo mode. This is for when you leave the device idle for a few minutes: Each one will start flashing the 1-16 LEDs according to the tempo set. Is there any way to turn this off? It's distracting when I'm thinking. The only info I could find was for the TR-8 (not TR-8S) which said to hold down PTN SELECT while turning it on: this does not work for the TR-8S. I'm assuming that if it is possible, the -09/-08/-03 will each be slightly different. Couldn't find anything in the manual either. I'm not exactly sure what this feature is technically called so I'm having a hard time googling an answer. Thanks!