VGA to Scart Problems

HI All

I'm hoping to connect a MAME PC to an LG CRT with the RGB SCART input.

- My MAME PC is running a HD8490 with CRT Emudriver and Groovymame installed.

- I have assembled the VGA to SCART cable based on this Post http://forum.arcadecontrols.com/index.php?topic=77370.0.

- In vmmaker I have Monitor presets set to Generic 15.7kHZ and the Composite sync setting is enabled.

When Connected to the CRT the picture is nice and sharp but it's rolling flat out, I think the is because it's not getting sync? I put my multimeter on Pin 20 of the SCART plug and it reads 5v, which its TTL I think. If the PC was out putting C-sync shouldn't it be 0.3V?

Any suggestions?

Cheers, Ben