Hi thanks for your replies - the scart lead is brand new - the av connection on tv works as I use this for other consoles and tv - suspect the problem lies somewhere within the console but will try on another tv - strange this is this has happened on this and 2 other saturns - exactly the same problem - perhaps this is a common fault on older models? any more advise really helpful thanks
I've found brand new RGB leads for many retro consoles are less than ideal, the last Saturn one I bought didn't even have pins 8 and 16 connected up, let alone connected up the wrong way round like a lot of leads.
Do you know if composite video is working okay? You could try it on a second scart socket on the tv if it has one, they generally don't support RGB
You'd have to be very unlucky to have more than one console with exactly the same faults, I suppose it could be a bad solder joint on the AV socket, or on the video chip CXA1645, or something inbetween the the chip and the socket (or even the signals feeding the chip). The CXA1645 is used a fair bit, so a schematic should be easy to find on the web showing which legs are the RGB in and out signals.