I'm thinking of making up a SCART adaptor to feed in 6v onto pin 8 in order to force the TV into widescreen. I can use a power supply or battery to do that but...I'm confused as to where the 0v side of the power supply should go. Can it be left unconnected, or should it be joined to an audio or video ground pin, or what? Does anyone have any insight?

Any of the ground pins, or preferably all of the ground pins - if you don't connect it, nothing will happen.

Don't feed it directly in though - feed it via a series resistor of 1K or so, 'just in case'.

Gosh, that was quick! I think every other signal pin has a corresponding ground pin, except pin 8. I'll be using composite video and audio so I could join it to one or all of those, but also would pin 21 (the chassis ground) do? This pin wouldn't actually be connected to anything on the source side but presumbaly would be connected to the TV when plugged in, or is pin 21 always connected internally in SCART plugs to all the ground pins anyway?

There's no guarantee that pin 21 would be connected, but obviously composite and audio ground will be so.

I'm curious as to why to want to do this.

Great, thank you Nigel. You have your uses.

<deep breath>

I have a media server, user interface is on a 8.5" touchscreen LCD monitor, audio plays through AV Amp, video plays on TV. I've only got a CRT TV though so it's practically impossible to get a true widescreen picture via a graphics card. So I've got a 4:3 desktop on the TV via composite video but I set all my videos to be displayed as anamorphic, so I need the TV to be in Wide mode. The desktop gets stretched but I will never use the desktop on the TV, it's just a blank empty space. But the videos will be stretched out to their proper aspect ratio. I'm getting fed up of keeping the TV remote handy and changing the aspect ratio each time I want to use the media server!

I have a demo video of the system at www.chris-simon.org.uk/meedio_demo.wmv if you'd like to see it in action.