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Author Topic: build a RGB Scart cable (Read 20232 times)

Offline Zozosoft

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Re: build a RGB Scart cable
« Reply #15 on: 2012.August.06. 08:36:54 »
Nice graphics! Which program used for drawing?

Prompt where I must connect Mode Switch and CSYNC
Switch from EP B6 to SCART pin 8 (and with the 470 Ohms to pin 16)
CSYNC from EP B5 to SCART pin 20, usually these also require a 100 Ohm resistor.

Offline SlashNet

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Re: build a RGB Scart cable
« Reply #16 on: 2012.August.06. 13:37:31 »
Thanks for help! :)

Quote
Which program used for drawing?
Photoshop only (drawing process relaxes me).

Offline Zozosoft

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Re: build a RGB Scart cable
« Reply #17 on: 2012.August.06. 13:57:23 »
Photoshop only (drawing process relaxes me).
When it is finished with the last two wires then possible use your graphics on Enterprise webpages?

And do you want some more relaxing?  :) If yes then can you make same nice graphics for other cables? (Printer, Serial, Joystick, ...)

Offline SlashNet

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Re: build a RGB Scart cable
« Reply #18 on: 2012.August.06. 14:10:43 »
No problem. :)

Offline Zozosoft

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Re: build a RGB Scart cable
« Reply #19 on: 2012.August.06. 15:39:28 »
No problem. :)
Thanks!
I will write the connection pinouts?

Offline SlashNet

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Re: build a RGB Scart cable
« Reply #20 on: 2012.August.06. 16:03:05 »
it would be nice

B2 - 4 is correct?
« Last Edit: 2012.August.09. 00:32:30 by SlashNet »

Offline Zozosoft

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Re: build a RGB Scart cable
« Reply #21 on: 2012.August.06. 16:13:01 »
B2 - 4 is correct?
Yes, both B2 and A2 are GND, it is on the Scart: 4, 5, 9, 13, 18, 21

Offline Zozosoft

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Offline ikduncan

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Re: build a RGB Scart cable
« Reply #23 on: 2013.April.01. 15:48:29 »
just built a cable. works ok on my EP64 with abit of sound interference (ground issues)
on my EP128 its is very bright colours with bleed/shimmer around edges.

are there different scart outputs for different boards? im thinking maybe higher resistors on the RGB 330/470?

Offline Zozosoft

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Re: build a RGB Scart cable
« Reply #24 on: 2013.April.01. 16:09:26 »
Quote from: ikduncan
are there different scart outputs for different boards? im thinking maybe higher resistors on the RGB 330/470?
Few days ago Bruce also recommended higher resistors.

The 100 ohms come from Hungarian magazine (1989).

Theoretically all motherboards same, but I does not rule out undocumented changes during the production.

Offline BruceTanner

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Re: build a RGB Scart cable
« Reply #25 on: 2013.April.02. 14:30:03 »
Quote from: Zozosoft
Theoretically all motherboards same, but I does not rule out undocumented changes during the production.
Not to mention the effects of 30 years on component values!

Offline ikduncan

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Re: build a RGB Scart cable
« Reply #26 on: 2013.April.02. 22:34:23 »
Hi bruce im in agreement.

I picked up a 64 and a 128 last week.

Made a cable up with 100R and is perfect on the 74 but major bleed of colours on the 128

Im thinking possible differnces on the issue of boards etc?

Offline BruceTanner

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Re: build a RGB Scart cable
« Reply #27 on: 2013.April.03. 10:21:16 »
Quote from: ikduncan

Im thinking possible differnces on the issue of boards etc?
It's possible but I don't think we're aware of any production differences - but zozo is the expert on that sort of thing! Internally there are only a few resistors between digital TTL logic and analogue RGB output - more likely one or more of those have become low in value over the years!

Offline Zozosoft

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Re: build a RGB Scart cable
« Reply #28 on: 2013.April.03. 10:26:15 »
This schematic contain the colour DAC resistors.
I will check some different version motherboards, about all using same values?

Offline ikduncan

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Re: build a RGB Scart cable
« Reply #29 on: 2013.April.07. 09:37:37 »
I have built a new cable with 330r on rgb.

Darker colours but still fuzzy edges/bleed.

 Any ideas where to look? What to change?