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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: odious on May 12, 2006, 08:27:30 PM

Title: A500 composite video - blank image
Post by: odious on May 12, 2006, 08:27:30 PM
Hi everyone.

I have an A500 but no modulator. Im trying to get composite video from it but all i get is a blank image at the tv. I know it is working fine because i asked a friend to lend his modulator so i could try it.

 I used  pin 12 (composite sync) and pin 16 (gnd) at the amiga connector. Do i need to join hsync + vsync + csync (pins 10, 11, 12)? I know there are some already made cables, but im a bit out of cash.

Regards.
Title: Re: A500 composite video - blank image
Post by: InTheSand on May 12, 2006, 08:57:52 PM
Hi,

If you're really stuck, I guess you could use the in-built monochrome composite video output...

But as far as I'm aware, the A520 modulator is required to produce the colour composite signal... You should be able to pick one of these up for next to nothing though.

 - Ali
Title: Re: A500 composite video - blank image
Post by: odious on May 12, 2006, 09:08:29 PM
Hi, indeed i could use the built in monochrome composite, but i want color.

As far as picking up material on ebay, been through that, postage costs are outrageous and wanted to do this on my own.

Regards,

Odious
Title: Re: A500 composite video - blank image
Post by: InTheSand on May 12, 2006, 09:11:06 PM
Well, not sure where you're from, but car boot sales and/or garage sales are a good source for this sort of thing.

I recently paid NZ$5.00 for an A520, and I'm sure you'd be able to find one for a similar amount in your local currency - keep looking!

Alternatively, if you're in Europe, you could use a TV with SCART and make an RGB cable.

 - Ali
Title: Re: A500 composite video - blank image
Post by: odious on May 12, 2006, 10:15:54 PM
There's no tradition on car boot sales here in portugal.

As you said, the scart could be made, but the objective was to use an old surveillance color monitor i have with composite video in since i dont have a tv at the room with scart.

Regards.
Title: Re: A500 composite video - blank image
Post by: amigagr on May 12, 2006, 10:48:33 PM
don't join for ANY reason the hsync + vsync + csync. i don't know if this will harm rgb port or not, the sure is that the sync signal combined with luminance and color with the proper circuits.
Title: Re: A500 composite video - blank image
Post by: Tenacious on May 13, 2006, 06:55:13 PM
I would use the monochrome composite until finding a official or at least tested solution.

I remember hearing something about a modification to the A520 to get S-video out.  Anyone?

Sinse the 1084s are starting to die, it would be great to find ways of adapting TVs to give large, clear images.  Maybe understanding the European SCART input is a good place to start.  US TVs don't have this input, but, could probably be modified.  The 1084 itself is little more than a TV with direct inputs to the RGB circuits and minus the tuner.  Has anyone ever found a schematic for the 1084?
Title: Re: A500 composite video - blank image
Post by: lauri_t on May 14, 2006, 11:04:17 PM
I am sure US tv's have RGB input. The signal inside the SCART is RGB.
Title: Re: A500 composite video - blank image
Post by: amigagr on May 14, 2006, 11:28:29 PM
schematics (http://staff.washington.edu/rrcc/)
service manual (http://www.epanorama.net/links/servicemanuals.html) look at the bottom
Title: Re: A500 composite video - blank image
Post by: alenppc on May 15, 2006, 05:14:54 AM
Quote

lauri_t wrote:
I am sure US tv's have RGB input. The signal inside the SCART is RGB.


No they don't. They usually have S-video and the more recent ones have YCrCb (component) input which is incompatible and not easily adaptable to RGB.

Title: Re: A500 composite video - blank image
Post by: Ohforf on May 15, 2006, 05:39:25 AM
There is a A1000 Hardware Hack for Color Composite Video.
It might be possible to do something like this with a A500.
I'm too lazy to look at the Schematics now, sorry.
Look at my Post in this Thread (http://www.amiga.org/forums/showthread.php?t=20670) and take a good look at the A500 Schematics.
It won't be easy, a A520 is less Trouble.
Title: Re: A500 composite video - blank image
Post by: orange on May 15, 2006, 07:16:14 AM
how about modifying TV to get RGB input? as everyone knows RGB is much much better than composite.

IIRC, every TV should be able to handle RGB one just needs to find it on schematics if there is no SCART, right?

if you have VHS video with 'full' SCART you could use it, the quality wont be very good but at least you'll get colour..
Title: Re: A500 composite video - blank image
Post by: odious on May 16, 2006, 12:42:52 AM
Hi everyone!

Thanks for all the tips and infos. I built the rgb scart and it worked very well. My tv set has three scart inputs but it works on only two, the one that doesnt work, displays the same blank screen as like when i connected csync to the composite input.

I Had to hack a db 25 pcb type and cut it to make 23 pin. Now im waiting for a friend to send some proper 23 pin d sub from canadá, because when i ask for that type of connector here in portugal, all i get is "it doesn't exist" or "pheeewww... big trouble".

Meanwhile, i'll see if i can get an old vcr to hook to the 500 and use the composite out to the monitor.

Regards,

Odious
Title: Re: A500 composite video - blank image
Post by: CLS2086 on May 16, 2006, 08:52:48 AM
Hi,
you could get a complete "AMIGA to RGB Peritel/Scart" cable by Ebay for 15/20e...
http://cgi.ebay.fr/Amiga-RGB-Scart-Cable-2-m-for-TV-or-monitor-NEW_W0QQitemZ8284493578QQcategoryZ98928QQrdZ1QQcmdZViewItem

http://cgi.ebay.fr/COMMODORE-CAVOSCART-VIDEO-AUDIO-X-AMIGA-500-600-1200_W0QQitemZ8810358353QQcategoryZ4598QQrdZ1QQcmdZViewItem

http://cgi.ebay.fr/Long-Amiga-RGB-Scart-Cable-5-m-for-TV-or-monitor-NEW_W0QQitemZ8285744089QQcategoryZ98928QQrdZ1QQcmdZViewItem

you can't use a VHS to get color, because it only use composite pins of the Peritel/scart