LED TV Grundig Model: 40 VLE 5324 BG --blue layer shifted, where start to repair

[roffelkartoffel]

Hey fellas,

I got the aforementioned TV for free due to image problems. The blue "layer" is flickering for a few seconds sometimes (not exactly sure when switching to the used HDMI-channel) but stabilises after all. The issue with the blue "layer" is that it's shifted by approx 20-30 px to the bottom, red and green are fine (resulting in yellow).

I've already replaced the mainboard but had no luck so far. Have you any idea what possibly be wrong or where to look for further info?

Greetings from Germany