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General Category => Off topic => Topic started by: Rockj on 11:33, 20 January 07

Title: RGB Scart for Amstrad CPC6128 [moved]
Post by: Rockj on 11:33, 20 January 07
I could need some help figuring out how to get colors on my screen. I posted this is another forum: (http://nfggames.com/forum/index.php?showtopic=2554)

Quote
Hi.

Ive done quite some research now on my Amstrad Color Personal Computer 6128. Problem is that I find different types of wires and stuff everywhere. At the moment my male dpin6 goes to the amstrad and makes a female scart plug. ( http://usuarios.lycos.es/putusoft/emucpc/hardwaee.htm#8 ) . Does this sound correct? regarding sync/lum for example? I get nice and clear picture on my projector with svideo or composite. My projector supports scart/rgb too if I use a scart male to female vga adapter that followed the projector. With current cable I get no signal on the projector. With an earlier rev. of my cable - It gave signals but projector mentioned too high freq. when I was trying this. (but the picture was not as clear as it was now when using svideo/composite).

I'am wondering what I should do to get colors on my projector? Ive tried to connected it to my NEC Multisync 2080UXi too without success. (it says out of range). My last try is from the tip I readed on gamesx regarding to use old monitors as I know someone with a 21" old monitor which takes RGB on the monitor and connects it with VGA to my SCART-rgb/to/VGA converter. If I still get black and white then....I'm lost.

Anyone have any knownledge about the amstrad cpc 6128?

My projector is a Optoma H27.


Quick restate of problem: I do get clear picture on my projector and it supports all kind of modes and switching input from "Video" and "RGB" . Only working thru s-video and composite. Is black&white in "video" mode on projector and "chromo"green in RGB? Atleast green coloring.

Another question I have is... do the amstrad cpc sync on rgb green? I heard old systems do that, maybe that's my error? As far as I know you could sync on rgb green and vert/horz-sync.

I got a reply todo:
Quote
I once had an amstrad CPC464 and I remember it had two monitors available to it, a colour and a monochrome one. The video port outputs RGB and a (TTL) composite sync signal for the colour monitor and a normal video signal (video + sync) for the mono monitor.

If you are connecting this computer directly to your projector via it's SCART connector then follow the diagram on the website and make one (very important) addition. Connect 5 volts (available from your CPC's power supply) through a 180 ohm resistor to pin 16 of the SCART connector. This will put the projector into RGB mode. If the projector isn't in RGB mode it will display the monochrome video signal.

I have no idea what you are doing with VGA adaptors, timing of the video coming from your computer (TV) isn't compattible with any VGA monitor.

The CPC computers don't have any sync on the green signal -- most computer of this era don't.

I should stick to his advise? Electronics isn't my elite area, and I'm just afraid of hurting my projector if I do something wrong. Anyway, I got a friend next week (pro elec. engineer) who can take 5v from my MP2 modulator up to scart pint 16. Where should I put ground? Any of scarts ground pins?

Title: Re: RGB Scart for Amstrad CPC6128
Post by: robcfg on 16:49, 20 January 07
Though electronics it's not my area, I suggest you to read this page:

http://andercheran.upv.es/%7Eamstrad/docs/mods/scart.html (http://andercheran.upv.es/%7Eamstrad/docs/mods/scart.html)

It seems to be detailed but I cannot tell you of its accuracy.

Hope it helps!
Title: Re: RGB Scart for Amstrad CPC6128
Post by: Ygdrazil on 17:32, 20 January 07
Would be nice with WIKI article on this subject!

/Ygdrazil
Title: Re: RGB Scart for Amstrad CPC6128
Post by: Rockj on 18:05, 20 January 07
I found lots of different versions on internet. Anyway, my current one shows a pretty clear image on my projector - problem is that my amstrad is outputing monochromo. So I hope adding 180ohms on scartpin 16 will enable RGB :)

There is already some info on wiki, but not much and it also just makes me more confused on the subject: http://cpcwiki.eu/index.php/TV_SCART_cable
Title: Re: RGB Scart for Amstrad CPC6128
Post by: PulkoMandy on 20:54, 20 January 07
You can try removing the pin 6 of the Amstrad DIN. It is only used for the green monitor.

DIN >> SCART
1 >> 15 (red)
2 >> 11 (green)
3 >> 7 (blue)
4 >> 20 (sync)
5 >> 18, 13, 9, 5 (ground)
6 >> not connected

This cable works when plugged to an Atari or Commodore screen. You may need to add 5 or 9V to get auto-commutation on a TV or projector, but the pinout is correct :)
Title: Re: RGB Scart for Amstrad CPC6128
Post by: Rockj on 22:07, 04 February 07
Have you tested it on a TV?  I think it might be different for connecting to an Atari or Commodore screen.
Because ive tried the DPIN that you explain before, but pin 6 was connected ..and I dont remember if it gave picture at all or only black and whit as useall.

Im just wondering if I should try the 5v with 180oms on scartpin16. Abit afraid to destroy my projector or my pc monitor ..
Title: Re: RGB Scart for Amstrad CPC6128
Post by: Gryzor on 10:38, 05 February 07
Adding current to the pin is, I think, a common practice: although I've never done it myself, I keep seeing suggestion to that effect for various computers. The only difference is that you can actually try a 3V battery (is it three volts? The one with both poles on the same side of the battery?) instead of the CPC's 5 volts.

I agree that a projector is a very expensive thing to experiment upon - can't you find an old monitor?
Title: Re: RGB Scart for Amstrad CPC6128
Post by: PulkoMandy on 15:49, 09 February 07
the SCART pinout is the same for every monitor, TV or projector...
Maybe your projector can't display a RGB signal from the scart plug. In this case, a trick can be to plug the CPC to the VGA in of the projector, if you are lucky it will accept 15KHz sync from here...

The 5V is to enable auto-switching to the correct input mode on a TV, but isn't needed as long as you can switch the mode manually.
Title: Re: RGB Scart for Amstrad CPC6128
Post by: robcfg on 14:22, 25 February 07
Hey pulkomandy!

I've been trying to do a CPC->Scart cable too.

I've tried this pinout http://andercheran.upv.es/%7Eamstrad/docs/mods/scart.html (http://andercheran.upv.es/%7Eamstrad/docs/mods/scart.html) and yours.

The thing is I can see the colors right on my tv (an old 14" sony tv) but I cannot get the sync right. Here's a picture of what I get:

(http://img294.imageshack.us/img294/7773/dsc05574qn4.th.jpg) (http://img294.imageshack.us/my.php?image=dsc05574qn4.jpg)

Do you have any idea why I cant' get the CPC image right?

Edit:
The schematics of the CPCWiki (with the 1.5v source) and the one from the Unofficial Amstrad CPC resource work pretty much the same. I get the same result, colors are ok but sync doesn't work right.
Title: Re: RGB Scart for Amstrad CPC6128
Post by: robcfg on 00:49, 02 March 07
I finally did it!  :D

I had a problem with some cables but I managed to get everything according to the wiki schematics and, et voilá!

(http://img453.imageshack.us/img453/3262/dsc05582zv4.th.jpg) (http://img453.imageshack.us/my.php?image=dsc05582zv4.jpg)

(http://img413.imageshack.us/img413/7808/dsc05583tw6.th.jpg) (http://img413.imageshack.us/my.php?image=dsc05583tw6.jpg)

(http://img453.imageshack.us/img453/2994/dsc05584ob8.th.jpg) (http://img453.imageshack.us/my.php?image=dsc05584ob8.jpg)
Title: Re: RGB Scart for Amstrad CPC6128
Post by: Gryzor on 13:54, 02 March 07
Great, man, thanks for letting us know... and that loading screen is fantastic! ;D
Title: Re: RGB Scart for Amstrad CPC6128
Post by: robcfg on 01:26, 06 March 07
Hey Gryzor, if you liked the SCART cable you'll love this one!  ;D

With much less effort than the SCART cable I managed to get the CPC working with a PC power source.

(http://img339.imageshack.us/img339/4774/dsc05586vb0.th.jpg) (http://img339.imageshack.us/my.php?image=dsc05586vb0.jpg)

(http://img164.imageshack.us/img164/7438/dsc05587wp5.th.jpg) (http://img164.imageshack.us/my.php?image=dsc05587wp5.jpg)

I know this is not really the topic, but I thought it was good news to tell!

Do we have a section on Hardware Projects like these ones? I'll be making a second SCART cable for a friend and I'm planning on using a MiniITX power source instead of the standard ATX one. So I could be documenting each step of the process for the benefit of the Wiki's DIY fans.
Title: Re: RGB Scart for Amstrad CPC6128
Post by: Gryzor on 09:40, 06 March 07
Heya mate, great work... if you can document it it would be really great!

Actually there is a section on CPCWiki, it just wasn't so obvious. I've renamed the Sidebar element to point it out - you can go to "Tech docs-Tutorials", from there you can see a subcategory with hardware projects - anything that could populate it would be really really nice...

Thanks again!
Gryzor
Title: Re: RGB Scart for Amstrad CPC6128
Post by: stoodleysnow on 23:35, 15 October 07
 ???
Help
I am trying to make a SCART lead for my spare CPC 464 (I have 2 CPC 464s and one colour monitor). Both 464s work fine with the CTM644 monitor. But I would like to use both at the same time in separate places. I have attempted to make a SCART lead using the schematic on CPCWIKI. A colour signal does get through, but is skewed at an angle and multiplied or wrapped around the screen 4 or 5 times. I am using the 1.5V battery (without it the screen is black and white) but not the 9v battery, as my TVs have AV buttons. I have tested the lead with a multimeter, and the wires are all connected properly, with no crossed wires as far as I can tell. (6 is N/C, I want colour)
But on connection to the TV, the sync signal just doesn't seem to be getting through ???
Both 464s give the same result on two different TVs.
Yours confusedly
ME
Title: Re: RGB Scart for Amstrad CPC6128
Post by: robcfg on 18:20, 30 October 07
I would double-check if you got the right cables in the right pins. I got the same silly mistake (you can see the pictures in this same topic) because of my false assumption that cables on both sides of the SCART connector go to the same pins, which is not true.

I've tried also this schematics http://www.kjthacker.f2s.com/docs/mods/scart.html (http://www.kjthacker.f2s.com/docs/mods/scart.html) and it works fine with no need of the 1.5v battery, at least in my tv.