RGB SCART cable problem - not sure what is wrong..

[appiah4]

I have an RGB SCART cable wired pretty much the same way as this:



with the following exceptions:

• No optional composite
• R-G-B and Audio Ground on SCART plug are jointly connected to pin 17-18-19 on the RGB plug which are soldered together
• SCART Pin 18 to RGB Pin 13 Logic Ground is missing.
• SCART Pin 16 to RGB Pin 23 RGB selector has a 52 Ohm resistor.

I have tried it on 1 LCD and 1 Plasma TV - getting black screens on all. The tech who made it for me claims it's correct and works on his displays.


My questions:

• Would adding the optional composite help?
• Is the grounding an issue? should each channel be grounded seperately?
• Is lack of Logic grounding an issue?
• Should I try a higher ohm resistor on RGB select?
• Could my TVs be lacking RGB on their SCART? (LG 32LC2R ancient LCD, LG 50PM6800 Plasma)

Any help would be appreciated, kinda losing my mind over this.

[Jope]

Originally Posted by appiah4

[*]Would adding the optional composite help?

No

[*]Is the grounding an issue? should each channel be grounded seperately?

It shouldn't cause a black screen. Potentially a bit more interference, but in practice it rarely matters.

[*]Is lack of Logic grounding an issue?

The grounds are usually just connected together inside the TV anyway.

[*]Should I try a higher ohm resistor on RGB select?

Yes, but don't be disappointed if it doesn't help.

[*]Could my TVs be lacking RGB on their SCART? (LG 32LC2R ancient LCD, LG 50PM6800 Plasma)

Maybe, but not likely. Did you check the user manuals?

[appiah4]

Originally Posted by Jope

No

It shouldn't cause a black screen. Potentially a bit more interference, but in practice it rarely matters.

The grounds are usually just connected together inside the TV anyway.

Yes, but don't be disappointed if it doesn't help.

Maybe, but not likely. Did you check the user manuals?

Thanks Jope. The manuals say absolutely nothing about RGB on the SCART port and the TV has no option of enabling RGB mode on the euro scart av in manually. I'm considering buying an RGB SCART to HDMI converter to save myself the hassle if only I could verify the cable works..

I believe I have a 75 Ohm resistor somewhere, I'll solder it onto the RGB Select and see if it makes a difference.. It probably won't

There is no way of getting a Y-Pb-Pr output from the Amiga's RGB is there? Has anyone tried that? I know S-Video is possible, but the TV has no S-Video in either.. at least that's easy to break into component.

[demolition]

The input impedance on the RGB select pin might not be correct, so you should try to measure the voltage while it is hooked up to the TV. If the voltage is not correct, it will not switch to RGB mode and thus not display anything.

[appiah4]

Originally Posted by demolition

The input impedance on the RGB select pin might not be correct, so you should try to measure the voltage while it is hooked up to the TV. If the voltage is not correct, it will not switch to RGB mode and thus not display anything.

What should be the correct value? The pinout diagram shows a 75 ohm resistor on this pin only, I'm confused - why would the impedance be off?

Some people who had similar issues with similar TVs appear to have removed all the resistors and some cabling, and went with essentially this cable, and report it working, maybe I should try this?

[demolition]

The 75 ohm resistor forms a voltage divider with the input impedance of the SCART connector in the TV. If the input impedance of the SCART input does not follow the specs, which many modern TVs does not do, the voltage will be incorrect. Measuring the actual voltage of this pin will tell you if it is the case or not.

One could add a ~2V zener diode between the pin and Gnd which would make it work even if the input impedance was too high.

[utri007]

I have 32" LG lcd-tv and it doesn't have a RGB Scart at all. So it is possible reason for your problems.

[appiah4]

Originally Posted by utri007

I have 32" LG lcd-tv and it doesn't have a RGB Scart at all. So it is possible reason for your problems.

I fear this is the problem.. Ill order an RGB SCART to HDMI converter from Aliexpress...

[demolition]

I normally see 'RGB' written next to the SCART plugs on TVs which has RGB inputs.

[appiah4]

Originally Posted by demolition

I normally see 'RGB' written next to the SCART plugs on TVs which has RGB inputs.

Nothing here, just a symbol with a screen, one arrow going in, one arrow going out..

[demolition]

It might not be a general rule that they would indicate it but it could very well be that your TV does not support RGB as not all TVs do. After looking it up, I see that they could also use a symbol with a screen and three dots to indicate RGB like you see here on the right:

[appiah4]

Originally Posted by demolition

It might not be a general rule that they would indicate it but it could very well be that your TV does not support RGB as not all TVs do. After looking it up, I see that they could also use a symbol with a screen and three dots to indicate RGB like you see here on the right:

Yeah my old CRT had the one on the right (SONY), but the LG has one similar to the one on the left. I'm guessing it's not wired for RGB at all, which sucks bad, but it is what it is. At least the cable is good, and now I can look into an RGB SCART to something converter. What would cause the least lag? Keeping it analogue would probably be best so maybe I should look for RGB SCART to Component? But that would also require active conversion.. I'll probably buy a SCART RGB to HDMI adapter and wash my hands clean.

[Daedalus]

Yep, SCART to HDMI is probably the way to go. Unless you want to use composite (ugh), you'll need active conversion. Worrying that there's no RGB support at all - even TVs with one SCART socket that I've seen have had it.

[appiah4]

Originally Posted by Daedalus

Yep, SCART to HDMI is probably the way to go. Unless you want to use composite (ugh), you'll need active conversion. Worrying that there's no RGB support at all - even TVs with one SCART socket that I've seen have had it.

Its an LG so they cheap out on weird things. I sisnt have the budget for a Panasonic and dont regret it still its pretty crappy.

Bought this, wish me luck: https://www.aliexpress.com/item/Scar...668735504.html

It should arrive in a month or so, I'll let you know if it works, and with how much lag, ghosting etc. It sure can't be worse than composite.

[demolition]

I have that SCART-HDMI converter and it is horrible when it comes to latency. Picture quality is otherwise decent though.
RGB to component is lag free, however it is hard to get correct colors.

I think some kind of scandoubler would be a safer choice (although also expensive), either external so it can be used with multiple devices, or an Indivision ECS if you have a 500 or 600. I'm not too fond of the AGA MkII though but it can work decently if you spend some time finding a good configuration (many people have uploaded something you can try out).

[appiah4]

Originally Posted by demolition

I have that SCART-HDMI converter and it is horrible when it comes to latency. Picture quality is otherwise decent though.
RGB to component is lag free, however it is hard to get correct colors.

I think some kind of scandoubler would be a safer choice (although also expensive), either external so it can be used with multiple devices, or an Indivision ECS if you have a 500 or 600. I'm not too fond of the AGA MkII though but it can work decently if you spend some time finding a good configuration (many people have uploaded something you can try out).

Thats pretty discouraging. Bought it after reading reviews from buyers and watching youtube reviews that said delay was agreeable ( [ Show youtube player ] measures added delay compared to CVBS composite to be around 55ms which I can live with..). Its at least cheap.. I cant shell out for an Indivision at the moment and couldnt find an even half decent priced scart to component adapter..

[demolition]

Let's hope the converter has improved since I got mine. It's several years old by now.
Also, there is a difference in latency on mine whether you are converting to 720p/1080p modes or VGA modes (640x480, 800x600 and 1024x768) so be sure to try out all modes and refresh rates.

[jarp]

Do not know about latency but picture quality of that particular unit is absolute crap. Get good scandoubler or get nothing and just use composite video.

[appiah4]

Originally Posted by jarp

Do not know about latency but picture quality of that particular unit is absolute crap. Get good scandoubler or get nothing and just use composite video.

Crap is probably subjective because that unit's output is certainly lightyears better than Composite video and doesn't compare badly to XRGB at all considering it's a fraction the price: [ Show youtube player ]

Not saying the scandoubler or Framemeister isn't the superior option, but shitting on this by saying composite is better really doesn't do that angle much good.

[jarp]

Ok i will try to be more productive, sorry. Not sure if there are differences in the revisions or something but my unit outputs so horrible picture that it literally hurts my eyes. Even my GF said that you will ruin your eyes watching that.

It different than in composite video though. Picture is sharp unlike composite video and colors are vivid. It is the movement. When something (like mouse) moves on the screen there are bad artifacts and somehow it literally hurts. I used it for few days and coughed up the money for better solution...