VOGONS


First post, by dreamblaster

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Hi,
I teamed up with Retro Erik to create a good CGA2SCART converter - "Retro Erik edition".
I will post results in this thread.

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !

Reply 1 of 16, by dreamblaster

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First generation CGA 2 SCART converter, developed together with Retro Erik :

CGA2SCART_ERIK.jpg
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CGA2SCART_ERIK.jpg
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The final revision of this generation PCB works well, but it does not implement 'the brown fix' (logical yellow is replaced by brown in CGA monitors, if you make a converter it should provide for this too).
Not a big issue, but still we continued development, and also solved this, for next generation pcb's. (will post more soon)

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !

Reply 2 of 16, by Jinxter

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This is the CGA2SCART i made back in 2017.

https://www.youtube.com/watch?v=ymulGiO4NrI

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Check out my YouTube channel: Retro Erik https://www.youtube.com/channel/UCSUf7nCpwTgFbjGmcTYGZEQ
My collection: https://retro.hageseter.com

Reply 3 of 16, by Jinxter

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And this was the prototype of the improved version we developed together. As you can see in the video we made a mistake, so modifications had to be made.
Take a look: https://youtu.be/YIxVnInL0QI

The work "ELUSIVE" seen 12 seconds into the video, should be the colour brown. This is a shortcoming in this design. Instead of brown, it's dark yellow.
How big a problem is this for you? Please let us know.

Commodore 128 also uses digital RGB, so this converter can also be used on a Commodore 128.
Since EGA digital RGB the converter also can also be used on EGA 320x200 and 640x200, in any number of colours. The 640x350 resolution does not work.

As you can see we added a jack for sound in, so that you can feed your SCART TV with video and sound in the same SCART cable.

Check out my YouTube channel: Retro Erik https://www.youtube.com/channel/UCSUf7nCpwTgFbjGmcTYGZEQ
My collection: https://retro.hageseter.com

Reply 5 of 16, by Jinxter

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I took some pictures today. All pictures are here: https://1drv.ms/u/s!AjpBupGs3pEBhZNTnjKF128i9cDyUA?e=G4C1X5

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  • PX3_CGA CRT 640x200x16.jpg
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    640x200 in 16 colours.
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  • CheckIT.jpg
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    CheckIT.jpg
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    319 views
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    Stable pictures. Stable borders.
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  • PX3_CGA 640x200.jpg
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    640x200 b/w
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  • PX3_CGA 640x200x16.jpg
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    PX3_CGA 640x200x16.jpg
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    640x200 in 16 colours.
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Check out my YouTube channel: Retro Erik https://www.youtube.com/channel/UCSUf7nCpwTgFbjGmcTYGZEQ
My collection: https://retro.hageseter.com

Reply 6 of 16, by Benedikt

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I think it's interesting that your flat panel TV appears to blend adjacent colors in the 640x200 modes.
Maybe it uses an NTSC notch filter for all kinds of analog input and not just for composite signals.

Reply 7 of 16, by matze79

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dreamblaster wrote on 2020-07-23, 14:48:

First generation CGA 2 SCART converter, developed together with Retro Erik :

CGA2SCART_ERIK.jpg

too bad this would not fit many screens because of space limitations, specially when wall mounted 😒
Looks good.

Combine it with a RGB2HDMI Chip and you get CGA2HDMI 😁

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Reply 8 of 16, by dionb

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dreamblaster wrote on 2020-07-23, 14:41:

Hi,
I teamed up with Retro Erik to create a good CGA2SCART converter - "Retro Erik edition".
I will post results in this thread.

Maybe I'm a bit slow here, but given that SCART supports multiple signal types, which one/ones is this supporting?

CGA RGB -> SCART RGB?
CGA composite -> SCART composite?
Both? Or something else?

And what about NTSC vs PAL?

Whatever it is exactly, it's looking good though 😀

Reply 9 of 16, by Jinxter

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dionb wrote on 2020-07-28, 08:26:
Maybe I'm a bit slow here, but given that SCART supports multiple signal types, which one/ones is this supporting? […]
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Maybe I'm a bit slow here, but given that SCART supports multiple signal types, which one/ones is this supporting?

CGA RGB -> SCART RGB?
CGA composite -> SCART composite?
Both? Or something else?

And what about NTSC vs PAL?

Whatever it is exactly, it's looking good though 😀

Its RGBi (CGA RGB) to SCART RGB.
No composite. Composite from the CGA cards that have composite, is a different port. RCA
I don't think RGB has a different signal for NTSC and PAL - but please correct me if i am wrong.

Check out my YouTube channel: Retro Erik https://www.youtube.com/channel/UCSUf7nCpwTgFbjGmcTYGZEQ
My collection: https://retro.hageseter.com

Reply 10 of 16, by Benedikt

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Jinxter wrote on 2020-07-28, 08:33:
Its RGBi (CGA RGB) to SCART RGB. No composite. Composite from the CGA cards that have composite, is a different port. RCA I don' […]
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dionb wrote on 2020-07-28, 08:26:
Maybe I'm a bit slow here, but given that SCART supports multiple signal types, which one/ones is this supporting? […]
Show full quote

Maybe I'm a bit slow here, but given that SCART supports multiple signal types, which one/ones is this supporting?

CGA RGB -> SCART RGB?
CGA composite -> SCART composite?
Both? Or something else?

And what about NTSC vs PAL?

Whatever it is exactly, it's looking good though 😀

Its RGBi (CGA RGB) to SCART RGB.
No composite. Composite from the CGA cards that have composite, is a different port. RCA
I don't think RGB has a different signal for NTSC and PAL - but please correct me if i am wrong.

Having a pair of solder pads for an RCA cable certainly wouldn't hurt.
Strictly speaking, RGB obviously has a different signal, because it is by definition neither the NTSC nor the PAL color standard.
Besides the obvious, NTSC does have some minimal offset between blanking black and signal black, if I remember correctly, whereas they are identical for PAL, but I strongly doubt that any CGA composite output ever implemented the NTSC specification in such intricate detail.
All of this should however be largely irrelevant, because we are far away from talking about color spaces, anyway.

Reply 11 of 16, by dionb

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Jinxter wrote on 2020-07-28, 08:33:
dionb wrote on 2020-07-28, 08:26:
Maybe I'm a bit slow here, but given that SCART supports multiple signal types, which one/ones is this supporting? […]
Show full quote

Maybe I'm a bit slow here, but given that SCART supports multiple signal types, which one/ones is this supporting?

CGA RGB -> SCART RGB?
CGA composite -> SCART composite?
Both? Or something else?

And what about NTSC vs PAL?

Whatever it is exactly, it's looking good though 😀

Its RGBi (CGA RGB) to SCART RGB.
No composite. Composite from the CGA cards that have composite, is a different port. RCA

True - but it could be implemented in SCART as it has separate pins for composite.

I don't think RGB has a different signal for NTSC and PAL - but please correct me if i am wrong.

No different signals, but a different resolution which the output device needs to support - 480 scanlines for NTSC, 576 for PAL.

Reply 12 of 16, by Benedikt

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dionb wrote on 2020-07-28, 09:57:

No different signals, but a different resolution which the output device needs to support - 480 scanlines for NTSC, 576 for PAL.

That's not technically related to PAL or NTSC, but whether it is based on system M (525 lines toltal) or one of the others (625 lines total).
Any TV set should support both, 625 lines at 50Hz and 525 lines at 60Hz, either directly or after a manual V-Hold adjustment, regardless of the color transmission standard.
I can highly recommend ITU-R BT.470-6 (1998) as a reference.
It contains detailed descriptions of virtually all relevant analog television standards, including tolerances.

Reply 13 of 16, by Jinxter

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I tried my SCART2HDMI converter today. As you can see the left side av the screen is capped. I guess this is a problem with horizontal alignment? Anyone that has an idea how to fix this?

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  • Pictures from CGA.jpg
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    Pictures from CGA.jpg
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    CGA2SCART then SCART2HDMI. Problem with horizontal alignment.
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Check out my YouTube channel: Retro Erik https://www.youtube.com/channel/UCSUf7nCpwTgFbjGmcTYGZEQ
My collection: https://retro.hageseter.com

Reply 14 of 16, by Benedikt

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Jinxter wrote on 2020-07-28, 12:20:

I tried my SCART2HDMI converter today. As you can see the left side av the screen is capped. I guess this is a problem with horizontal alignment? Anyone that has an idea how to fix this?

I can only guess, here, but maybe it has a menu-selectable auto-adjust feature like many screens and crops the picture to the largest visible non-black area whenever you trigger it.
As a less-than-ideal workaround you could adjust the source signal itself through appropriate CRTC values.

Reply 15 of 16, by yawetaG

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Benedikt wrote on 2020-07-28, 12:58:
Jinxter wrote on 2020-07-28, 12:20:

I tried my SCART2HDMI converter today. As you can see the left side av the screen is capped. I guess this is a problem with horizontal alignment? Anyone that has an idea how to fix this?

I can only guess, here, but maybe it has a menu-selectable auto-adjust feature like many screens and crops the picture to the largest visible non-black area whenever you trigger it.

Yeah, looks like what some televisions do when set to the wrong type of handling for 4:3 and/or 16:9 aspect ratios. You'll need to play around with the television's settings to see what happens in which mode with which input/signal - with some televisions this can be set separately per input port, some televisions handle different input ports differently (so you need to change settings whenever using a different port), and some televisions simply don't like certain signals that get input to their analog ports.

Regarding the last point, don't expect to be able to get exactly the same kind of result on every television. Some TV models simply won't be able to display certain signals properly. Perhaps they won't like low resolutions, their digital conversion will fail with certain types of signal, they won't like the refresh rate, they can't handle NTSC over SCART, etc.
Also know that there are multiple versions of RGB out there (Japanese TVs use a slightly different version that means you need to use an adapter or special cable to avoid color issues).
That is why retro console gaming often uses special upscalers instead of a straight converter, to get a signal that most TVs won't have issues with.

Reply 16 of 16, by Jo22

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Wonderful thread, thanks for the pictures.!

Regarding the SCART issue.
SCART has a pin that can be used to switch between 16:9 and 4:3..

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