stuttering picture

[jasper1974]

Hi guys when i change channel to any HD channel i initially get a very slight stuttering/strobing sort of effect from the picture it normally only lasts a couple of seconds or so but when waching something like tennis its a bit more noticable and annoying as ball doesnt look smooth at all anyone got any ideas what could be causing it???

Am running VIx Hades18 but been on other versions too