구글 검색하니까 매뉴얼에 아래와 같이 나오네요. advanced 모드에서 수정 가능하네요.

SHOT LIGHT BRIGHTNESS Shot lights are positioned under each group to illuminate the extraction and give better visibility to the quality of the shot being dispensed. The brightness of these LEDs is dimmable from 0 to 100 percent. 1. Scroll to the Passwords title screen in the Home menu, select and enter the correct Password for the Advanced Menu. 2. Scroll to “Shot Lights Adj. Brightness” and press the button to enter 3. Scroll to the desired percentage brightness 0 to 100. Press enter to accept. 4. Long press to save and return to the Home Menu.

매뉴얼 입니다. https://slayerespresso.com/wp-content/uploads/2021/05/manual-steamLP-v2-0.pdf