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SCART output with VGA Cable - green color?

Started by eebuckeye, 02:15, 25 March 16

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eebuckeye

I bought a SCART to VGA cable and all I get is green shades with my VGA display.. Is there anything I need to do on the GX4000 console to use VGA with the SCART cable?


Thanks!

khaz


Tolkin

#2
If you bought only a cable for SCART to VGA it will normally be useless in your situation.
Some TV or or DVD Player can use or give a normal 31kHz VGA-Signal. (Like some METZ or Grundig TV-Sets, or Pioneer; Panasonic DVD Players). They can handle or create a VGA Signal, and normally this kind of cable is for these. Or your PC have to handle the GFX Card to bring "real" 15kHz Signals.

Your GX4000 output a 15kHz Signal which can not be used by a VGA-Monitor (Only old Multisync or some other VGA Monitors handle 15kHz Signals(CGA))
If your cable is a passive Cable (without a Converter) you wont get a Picture on a VGA-Monitor which not supporting 15kHz. (No Picture Buffer, no 15-31kHz conversion, Only VGA Connector wired direct to a Scart Plug)

You can use a converter like this for VGA :
CGA nach PC Wandler CM-397M, 99,00 €, Normwandler.de
or for HDMI this:
SCART nach HDMI Wandler CS-720PHD, 79,00 €, Normwandler.de
But as every converter you can get Problems in some Games (eg. Ghost&Goblins) or many Demos, because of the programming of the CRTC which a converter can not handle to get a smooth and stable Picture.

You can use More equipment for getting a better picture like this one i use for a few Arcade boards:
Scanline Generator - ArcadeForge

Or you ca use the "mysterious" RGB Framemeister which creates a very good picture but is much more expensive and the new ones have Japan "Scart" Connectors which makes it not easy building cables for it.

So hope it helped
Bye Tolkin

Munchausen

Quote from: Tolkin on 21:32, 25 March 16
If you bought only a cable for SCART to VGA it will normally be useless in your situation.
Some TV or or DVD Player can use or give a normal 31kHz VGA-Signal. (Like some METZ or Grundig TV-Sets, or Pioneer; Panasonic DVD Players). They can handle or create a VGA Signal, and normally this kind of cable is for these. Or your PC have to handle the GFX Card to bring "real" 15kHz Signals.

Your GX4000 output a 15kHz Signal which can not be used by a VGA-Monitor (Only old Multisync or some other VGA Monitors handle 15kHz Signals(CGA))
If your cable is a passive Cable (without a Converter) you wont get a Picture on a VGA-Monitor which not supporting 15kHz. (No Picture Buffer, no 15-31kHz conversion, Only VGA Connector wired direct to a Scart Plug)

You can use a converter like this for VGA :
CGA nach PC Wandler CM-397M, 99,00 €, Normwandler.de
or for HDMI this:
SCART nach HDMI Wandler CS-720PHD, 79,00 €, Normwandler.de
But as every converter you can get Problems in some Games (eg. Ghost&Goblins) or many Demos, because of the programming of the CRTC which a converter can not handle to get a smooth and stable Picture.

You can use More equipment for getting a better picture like this one i use for a few Arcade boards:
Scanline Generator - ArcadeForge

Or you ca use the "mysterious" RGB Framemeister which creates a very good picture but is much more expensive and the new ones have Japan "Scart" Connectors which makes it not easy building cables for it.

So hope it helped
Bye Tolkin

Or use a GBS-8220 board from ebay to convert to VGA (e.g. Video Converter CGA/EGA/YUV/RGB TO VGA Arcade Jamma Game Monitor to LCD GBS-8220). But your mileage may vary, and you will need to make the cables yourself. I actually bought a SCART->VGA cable to connect up my GBS and it was wired wrong so I had to rewire it, but it was still easier than building my own cable.

eebuckeye

I bought this cable:


Scart Cable to SVGA VGA 15 Pin HD Plug Lead 1 5M UK | eBay


This is not the correct cable?  Does the GX4000 output RGB on the SCART connector? 


I use a Sony video converter which handles PAL and a wide range of frequencies (including 15Hz).

Bryce

Yes, the GX4000 provides an 15kHz RGB signal on the SCART socket. If you are connecting the GX4000 to a device that can convert the signal 15kHz to 31kHz then it would be fine, but can the Sony really take a 15kHz signal on it's SVGA port? Check the datasheet.

Bryce.

eebuckeye

The person I bought the cable from said it was mainly for projectors only so he does not think it is the correct cable.  What does this mean?  How can I make sure to buy the correct cable?


Thanks!

Bryce

By telling us exactly what the Sony device model number is.

Bryce.


Bryce

That's one fancy piece of kit. According to the datasheet it looks like it should be able to handle the signal, however, the cable you have may not be wired correctly. You'll either have to check and modify that cable you have or make a cable up yourself.

Here's how it should be wired:
SCART Pin       ->              VGA Pin(s)
5                                      8
7                                      3
9                                      7
11                                    2
13                                    6
15                                    1
17                                    10, 11
19                                    13


Bryce.

PulkoMandy

the GBS8200 in its default configuration is not a very good choice, because the output signal is fixed at 60Hz and it does way too much signal processing (trying to deinterlace a progressive signal, etc).
However, some people did reverse engineering on the hardware and it's possible to reprogram it with some extra hardware to do the right thing (that is, just line-doubling).


My implementation of this is available here: GitHub - pulkomandy/gembascan
It was used during the Forever party for Thomson, CPC, and Sam Coupé prods on the bigscreen. It does not work yet with ZX Spectrum because it uses a bit unusual video timings.

Munchausen

Quote from: PulkoMandy on 14:58, 30 March 16
the GBS8200 in its default configuration is not a very good choice, because the output signal is fixed at 60Hz and it does way too much signal processing (trying to deinterlace a progressive signal, etc).
However, some people did reverse engineering on the hardware and it's possible to reprogram it with some extra hardware to do the right thing (that is, just line-doubling).


My implementation of this is available here: GitHub - pulkomandy/gembascan
It was used during the Forever party for Thomson, CPC, and Sam Coupé prods on the bigscreen. It does not work yet with ZX Spectrum because it uses a bit unusual video timings.

Nice job.

There are a few threads on here about this, the raspberry pi solution is quite nice (especially with the availability now of the pi zero).

If you do a search there are also a few different solutions to the problem where small amounts of noise (random white dots) appear on the screen.

Bryce

I have a WIP for this too, that removes the need for a RPi to be connected. As soon as I get time I'll finish and publish it. I only recently managed to get a GBS that had the problem, my original one doesn't have the issues.

Bryce.

eebuckeye

Found out my cable only had a few pins connected with video out going to green on VGA.  I can not rewire this cable because it only has a few wires..


How can I make sure to buy a SCART to VGA cable that has all wires attached?


Thanks!

khaz

Ask the seller?

At this point I'd just do it myself. Get a VGA cable, cut one end and solder the wires in a male Scart plug. You can even get audio out that way.

Bryce

Quote from: eebuckeye on 14:19, 31 March 16
Found out my cable only had a few pins connected with video out going to green on VGA.  I can not rewire this cable because it only has a few wires..

How can I make sure to buy a SCART to VGA cable that has all wires attached?

Thanks!

If that's the case, then the cable was made for Composite or S-Video, not RGB.

The only way to be 100% sure is to make it yourself.

Bryce.

eebuckeye

I have asked a few sellers and none knew the details.. ugh..

eebuckeye

#17
I built a SCART to RGB cable using Bryce's instructions.   I check all the connections with a meter and everything is correct, however, I do not get a picture from the GX4000 using my Sony converter and I tried every setting possible.  Is there anything special needed to output the RGB signal or just plug in the cable to the GX4000?


I used this same cable I built to connect my QL to VGA using a SCART female-female connector and it worked great!  I bought the QL to SCART cable from Sellmyretro.gom .  This tells me the cable is wired correctly since it is passing the QL RGB signal through to the VGA port.


Do I need to use a particular power input to get SCART RGB output from the GX4000?


Any suggestions?  Thank you!

Bryce

Which cable exactly did you build? I don't remember ever releasing plans for a cable that would connect to the GX4000 SCART port.

Bryce.

Munchausen

Bryce's cable takes RGB -> SCART, not SCART->RGB!

A SCART->RGB cable should be much simpler, just Red->Red, Green->Green, Blue->Blue, Sync->Sync, GND->GND, Left audio->Left audio, Right audio->Right audio

khaz

Pretty sure you messed up between sync in / sync out

eebuckeye

ARGH?!?   :D


I wired using this:

SCART Pin       ->              VGA Pin(s)
5                                      8
7                                      3
9                                      7
11                                    2
13                                    6
15                                    1
17                                    10, 11
19                                    13

That was not correct?  It works when I use my QL -> Scart then this cable to VGA.  :-)


Thanks!

Bryce

Ah, that list. Now I know what you're talking about. Yes, this should work on the GX4000. Can you post a picture of what you're getting on the screen?

Bryce.

eebuckeye

I'm not getting any picture on the screen but seems the cable is wired correctly since it works with my QL SCART cable (with female/female adapter).

Bryce

Hmmm, maybe the Sony isn't happy with the Sync signal?

Bryce.

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