On 21 Sep 2011, at 08:11, Mark Wickens wrote: I'm yet to determine whether this is down to the LCD panel it is driving being at limits or whether there is a slight issue with the video generation circuit. Once in a while, every couple of minutes or so the LCD looses sync and the picture is dropped. This only happens for a fraction of a second, then the picture is restored as was. If anyone has any ideas I'm all ears. For reference I'm using a Iiyama AS4637UT, an old but extremely capable 18.1" 1280x1024 native panel. If anyone is interested I can post the horizontal and vertical frequencies it is being driven at. It's most likely the LCD panel. They are very funny about refresh rates a lot of the time. Some prefer 59.9Hz and some 60Hz and some won't drive at anything other than that, while others will but shut the signal off after a while (my Samsungs all do this - very annoying) or they just have a brain-fart and blink off, and in your case come back on again (some just crash totally). It'd be interesting to see what the vertical and horizontal refresh rates are. -- Mark Benson My Blog: <http://markbenson.org/blog> Follow me on Twitter: http://twitter.com/mdbenson "Never send a human to do a machine's job..."