Bush CRT combi: on and off.
Bush portable CRT combi: on then off. I turned it on to see if I can still (in my late 40s!) hear the CRT flyback transformer whine, as I always could, and yes, I can. This is an extremely high-pitched whine (around 15Khz) which you’re only supposed to be able to hear as a child or teenager.
I am watching a documentary about British home computers from the 80s, and in the background they have some CRT monitors running, and I can hear the whine from those too.