Latest Mac Keyboard missing a Photoshop Channel Shortcut on TILDE key

Hi-I have just been given a new Mac keyboard to replace my old broken one. I have found a shortcut in Photoshop I use to view the channels, no longer works: I used to view the channels individually by pressing Apple 3, Apple 4 and Apple 5 and then I pressed the TILDE key (above the Alt key) to view a RGB colour overview on the file. What this did was keep me on the channel I had selected e.g. Green channel but show a preview of the RGB on the file. I need a solution to get this Tilde key working again! Many thanks!