Using VGA-SCART with advanceMAME on Linux

[collywobbles007]

Hi,
I'm trying to use advanceMAME on a Linux box that will output to my TV using a VGA-SCART cable that I made. That cable goes through an IC with a PIC programmed to block horizontal sync signals above 17KHz.

Unfortunately, I can't even get as far as testing this cable. I start with a PC monitor connected and try to set up advanceMAME with SCART TV settings...

device_video_clock to 5 - 50 / 15.62 / 50 ; 5 - 50 / 15.73 / 60

When I try to run advanceMAME (using Gridlee as the game) with this setting and a PC monitor connected I get...

Error setting the variable video mode information
video_init failed

This also happens in advv for all PAL/NTSC vdeo modes when I try to "TEST" a video mode.

If I set the device_video_clock to PC multisync settings it works fine. I don't really understand. If this is because a PC monitor is connected instead of a TV then how are you supposed to set up and test your TV settings since I can't boot Linux with it connected to the TV until I have set it up! Seems a bit of a chicken and egg situation to me. Am I missing some important settings in advmame.rc? The only line I've added to the default is the one above (which it says in the install.txt that it generates...but it doesn't).

Any help appreciated!

Thanks,
Collywobbles