help with a520 s-video hack

[Damiga]

@Damiga

Not tried the A520 hack but are you sure you are matching a PAL A520 to a PAL Amiga?

You also mentioned a SCART to YUV converter that had some Ghosting issues. The Amigas CSYNC signal is not compatible with modern video devices un-modified. You need to attentuate the output using a 330 ohm resistor. My SCART cable diagram is shown here:

http://eab.abime.net/showthread.php?t=47281

What Amiga do you have?
There are easily made hacks to add S-Video to the A600/A1200 or you can purchase an RGB to S-Video adaptor from Amigamaniac.com, though this is not as fun as hacking something together yourself

Ian

Hi Ian,

I've actually modified cable using your instructions earlier, it works great with my old CRT TV, so thanks for that =)

I also bought an amiga->scart cable that I've been using with the projector and the scart/yuv converter. The one I made myself with your instructions didn't work with the scart/yuv converter but the one I bought did.
And the cable I bought don't work on my CRT TV, The picture "rolls".

I actually had the same problem with the homemade cable on the CRT before I modified it with your instructions. The only modification was actually changing a resistor(I think it was a 180ohm that I changed to a 330ohm) so I guess that the cable I recently bought has a resistor lower than 330ohm and for some reason that makes it work with my projector. I haven't bothered to investigate that further since I could piece together a working combination of cables and CRT/projector.

On to the a520...
I'm pretty sure it's a PAL A520, The NTSC "jumper" on the circuit board is open(looks clean so I doubt that it's ever been closed) and the crystal is 4,something MHz and I understand that a NTSC version should have 3,something.

I've tried the A520 on my Amiga 500+ and on my A600, I don't dare to try it on my A1200s before I got it working on the a500 or a600.

I know there are other options for me than modifying the A520, but I'm not doing it out of necessity, I'm doing it for fun and it's a challenge

[Damiga]

Hello!
I didn't try the A520 mod for Y/C output, but since you speak about the YUV input of your projector, remember that YUV is DIFFERENT from Y/C.
Y/C means separated luma (brightness) and chroma (color) signals
YUV (also YCbCr) means luma signal (Y), U blue color minus luma signal (B-Y), V red color minus luma signal (R-Y)
 
So Y/C output is not compatible with YUV.

Yes I know, and I'm NOT trying to connect it(modified A520) to the YUV/YCbCr ports on the projector.