OLED brightness adjust?

I just picked up a second Artist Mix, and the OLEDs at the top are about 60% of the brightness of my other Artist Mix. That's a huge difference. It's driving me nuts.



Does anyone know of a 'secret' key combination to access some kind of internal settings to increase the brightness on the darker one? In the EuCon app, there is only brightness settings for the Atrist Control's touchscreen.