This thread might help:
https://clubjazz.org/forum/index.php?topic=7958.0Basically, you can’t actually turn the unit off completely, but you can blank the screen. Bizarrely, you don’t do that using the on/off button. Instead, you can either ignore the start-up warning screen, and after a few seconds the screen will blank (except for a very faint digital clock); or you can tap the brightness button until you get an “off” setting. In both cases the radio will continue playing (or, presumably, any other audio source - I’ve not tried the USB option) unless you’ve used the on/off button, which switches off all audio inputs.
I’ve not seen the moving “screen saver” clock, that may be a new feature in latest models. To get a decent clock on mine, I have to first enable the alternative skin (which gives you a clock button on the home screen), then adjust the settings to give the desired type of clock (digital or analogue).