Setting refresh rate on Nvidia 6800 card for TV output

[neptunecomptech]

Hi,

I'm using a Nvidia GeForce 6800 card with Windows 8 on a new machine.... I realise it's an old card, but I specifically need the S-VHS output it offers.

I'm using it in the UK with a PAL TV (standard - Not HD) and have the latest drivers. The software seems to allow 2 refresh rates 25 Hz and 29 Hz - However, the Nvidia Control Panel always seems to default to the 25 Hz - If I change the TV screen size to 480, it allows me to choose 29 Hz, but as soon as I click apply it goes back to 25 Hz.

I did somehow manage to set 29Hz once, but no idea how I did it and can't replicate it - and I really have tried hard!

Does any one know of any known issues or how I might get around this, as the 25Hz causes flickering on the TV, but the 29Hz didn't seem to when I had it briefly running?

Thanks for your help!

 

[Sunius]

Did you try creating custom resolution with custom refresh rate in Nvidia control panel?

I should note though, Microsoft said they don't support displays below 1366x768 resolution. However, I'm not sure whether it's the thing that causes your problem.

 

[danny2000]

Try checking to see if you need to download your monitor's driver file, which usually enables supported resolutions and refresh rates.

 

[neptunecomptech]

The custom resolutions/refresh rates seem to be for the PC screen output, and not applicable to the TV screen output (s-VHS)?

The highest resolution it offers is 1024 x 786 (which is fine for me), but defaults to 576i (25Hz). For each resolution it also gives 480i (29Hz), but setting this has no effect - It goes straight back to 25Hz.

Any ideas?

 

[neptunecomptech]

I realise I didn't make myself clear about what I'm doing... I'm outputing to both the PC screen and TV screen together (extending the desktop across both).

The PC screen is absolutely fine, but it's the TV refresh rate that's causing the problems.