M8 box on plasma through converter - How to deal with screen stuck on coloured stripes

[AC Question]

Hi I'm a novice to Android TV and we bought an m8 box for our old 42" plasma Samsung. Worked beautiful and the system was working great through kodi but then after two weeks now when we turn it on it stays on coloured vertical stripes. Been searching but there's no direction for finding technicians to help on this one...