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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: DrDekker on May 11, 2007, 01:00:26 PM

Title: PC Graphics Card Hack
Post by: DrDekker on May 11, 2007, 01:00:26 PM
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?

 
Title: Re: PC Graphics Card Hack
Post by: spirantho on May 11, 2007, 01:06:09 PM
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. :)
Title: Re: PC Graphics Card Hack
Post by: DrDekker on May 11, 2007, 01:17:04 PM
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. :-(
Title: Re: PC Graphics Card Hack
Post by: rkauer on May 11, 2007, 06:38:31 PM
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!
Title: Re: PC Graphics Card Hack
Post by: DrDekker on May 11, 2007, 08:43:06 PM
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?

Title: Re: PC Graphics Card Hack
Post by: alexh on May 11, 2007, 09:17:26 PM
You can get some scandoublers as cheap as $50 but they are only 16-bit
Title: Re: PC Graphics Card Hack
Post by: Zac67 on May 11, 2007, 09:41:48 PM
Quote
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).