Annoyingly, I'd presumed this must be impossible! I treated my Sam to a Quazar scart cable a while ago but as I have to share use of the telly it would be very handy to be able to use my monitor as well.
http://cgi.ebay.co.uk/COMPOSITE-S-VIDEO-AV-TO-VGA-CONVERTER-TRANSCODER-SVIDEO_W0QQitemZ350308258612QQcmdZViewItemQQptZUK_ConsumerElectronics_VideoSwitches_SM?hash=item518fffd334 That looks like the right sort of device but isn't there also an issue with the Sam not having a standard scart configuration?
