PC Graphics Card Hack

[DrDekker]

Has anyone ever attempted to create a scandoubler by hacking a PC graphics card with SVHS input?

I recently picked up a (working) MX480, 64Mb, 8xAGP card with SVHS for a quid at a carboot.

This got me wondering if it would be possible to get a vga output simply by powering up the card and connecting it up to my old CD32.  I'm sure there'll be a fair bit more to it than that to get a decent display - but is it feasible?

 

[spirantho]

Are you sure that's an input? Almost all SVHS jacks on SVGA cards are output so you can connect your PC to a telly. If it's really an input it should have a Bt878 or CX23882 chip on it somewhere.

And no, it's not trivial to do. Sorry.

[DrDekker]

Yes - it's actually VI/VO.  I've also got a few more boards including an analogue TV PCI and a digital TV PCI - all with SVHS in.  But I'm not going to hack any of those as they cost me money.

I'll take a butcher's and check for those chips.

I thought it might not be that easy - but had hoped that a basic vga output might be a possibility without software. :-(

[rkauer]

Sorry to inform: you cannot put a card like that "just behind" your CD32 to work alone.

These type of cards needs:
- power supply (on several pins);
- EXTERNAL CLOCK lines;
- Drivers and even some programs in order to run.

Best way is put the card into a peecee, install the needed drivers and use it like a regular scandoubler/flickerfixer.

BTW: If you got a Mediator, there are some Voodoo cards with VI/VO plugs on!

[DrDekker]

Thanks for that rkauer!

What I thought was that if it were possible, then I'd make a SVHS adapter for my A1200, then connect that to the video card to drive my TFT.

At the moment I connect my A1200 using the composite on my PC's digital TV card.  The results aren't that brilliant of course - perhaps I should make a composite-to-SVHS adapter instead?

[alexh]

You can get some scandoublers as cheap as $50 but they are only 16-bit

[Zac67]

DrDekker wrote:

At the moment I connect my A1200 using the composite on my PC's digital TV card.  The results aren't that brilliant of course - perhaps I should make a composite-to-SVHS adapter instead?

The screwed composite signal won't get any better when converted to super video - better convert directly from RGB to svideo; I've used a cheaply bought Hama genlock and the picture was quite good (not as good as RGB though).