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CGA to SCART adaptor

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    #16
    CGA to SCART in Toshiba T1000

    Hello to all!I recently made a CGA to SCART adapter for my Toshiba T1000.
    I used this schmematic:
    adapter-cga-scart.jpg
    from this site:http://electroschematics.com/377/cga-scart-adapter/
    As you can see in the attached images the picture is perfect in my LCD tv but you must know that there are 2 errors in the circuit:
    a)You don't need to connect the circuit to pin 7 of the CGA port-connect it instead to +5v(and -5v respectively to GND)
    b)On the SCART side connect the G(green signal) to pin 11 of the SCART plug and not to pin 4 (as shown in the circuit)
    And now some photos from my tv:
    Image8 (Small).jpg
    Image3 (Small).jpg
    Image4 (Small).jpg
    Image5 (Small).jpg
    Last edited by angel_grig; July 20, 2011, 08:38 PM.

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      #17
      Originally posted by FishFinger View Post
      It should work with EGA with only a small alteration. Instead of connecting the three 1.5K resistors together at pin 6 connect them to each of the secondary RGB pins (2, 6, and 7 iirc)

      Is the yellow/brown issue a problem with EGA? I thought EGA solved that by changing the palette rather than hardware trickery in the monitor.

      I'd double check. Most TVs claim to support NTSC, but it seems they really just mean 60Hz, very few of them seem to actually support NTSC colour.
      When EGA is in a 16-color mode, its output is exactly the same as CGA, RGBI. When in a 16/64 color mode, its output is RrGgBb. Also, I wonder how many SCART TVs can handle the 21.85Khz scan rate of an EGA 350-line mode.
      My Retro Computing and Vintage Gaming Blog : http://nerdlypleasures.blogspot.com/

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        #18
        15Khz RGB CGA Component Video to VGA Converter Scaler

        Ebay Item: 250375733782

        Has anyone tried one of these?
        GEEKS WITH A GRUDGE!

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          #19
          Originally posted by gerrydoire View Post
          15Khz RGB CGA Component Video to VGA Converter Scaler

          Ebay Item: 250375733782

          Has anyone tried one of these?
          Note, that the unit is for 15.75khz ANALOG RGB, such as the video outputted by the Apple IIgs, Atari ST, Amiga, and Tandy CoCo. CGA and EGA are TTL Digital RGB and require a converter like shown at the beginning of the thread. My PC Transporter in the Apple IIgs actually has such an adapter (small board on top labelled ColorSwitch) to allow CGA video to be shown on the analog RGB monitor the IIgs typically comes with. The adapter is quite a complex circuit compared to the one shown on this thread, but it likely shows brown correctly.

          pctrans.jpg

          Comment


            #20
            Originally posted by angel_grig View Post
            Hello to all!I recently made a CGA to SCART adapter for my Toshiba T1000.
            I used this schmematic:
            [ATTACH=CONFIG]6258[/ATTACH]
            from this site:http://electroschematics.com/377/cga-scart-adapter/
            As you can see in the attached images the picture is perfect in my LCD tv but you must know that there are 2 errors in the circuit:
            a)You don't need to connect the circuit to pin 7 of the CGA port-connect it instead to +5v(and -5v respectively to GND)
            b)On the SCART side connect the G(green signal) to pin 11 of the SCART plug and not to pin 4 (as shown in the circuit)
            I found that circuit when I was looking to build mine, but assumed it was wrong because the PC doesn't put 5V on pin 7.

            Which part of the circuit connects to -5V though?

            Comment


              #21
              Over on the Commodore 128 board we have a active thread with lots of designs. The C128 rgb out is the same as cga (i.e. uses a cga monitor for display)


              http://www.commodore128.org/index.ph...19331#msg19331

              Later,
              dabone

              Comment


                #22
                Originally posted by FishFinger View Post
                I found that circuit when I was looking to build mine, but assumed it was wrong because the PC doesn't put 5V on pin 7.

                Which part of the circuit connects to -5V though?
                You connect the -5v to GND eg to pin 1 of the CGA port (as you can see pin 1 of the CCA port and pins 13,9 and 5 of the SCART plug are connected together so you can attach the power in any of these locations)

                @dabone:nice link!thanks!
                Last edited by angel_grig; July 31, 2011, 09:58 PM.

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                  #23
                  MVC007 RGB,MDA,CGA,EGA to VGA Converter

                  Ebay Item number: 320688888731

                  Will this thing allow me to connect a CGA or EGA outputting PC to a VGA Monitor directly?

                  Thanks
                  GEEKS WITH A GRUDGE!

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                    #24
                    Another interesting device:

                    http://www.provantage.com/miracle-bu...l~AMRCL02Y.htm

                    Anyone ever buy one of these and attach it to a Vintage CGA or EGA PC?
                    Last edited by gerrydoire; August 20, 2011, 10:12 PM.
                    GEEKS WITH A GRUDGE!

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                      #25
                      I don't know about the $259 video adapter, but eBay is flooded with $36 video adapters from China. I got one of the latter, but only briefly tested it with an analog 15 kHz signal. I should try a TTL signal as well. It supposedly will work, but may have a bit of lag so if you're playing fast-paced action games in CGA it might not be your ideal buy.
                      Anders Carlsson

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                        #26
                        Many of those ebay video adapters are designed for converting arcade machines. And people who are into arcade stuff often use "CGA" to mean any 15KHz RGB signal - usually analogue, rather than PC-style TTL.

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                          #27
                          Does anybody have the schematics for the circuit posted in message #1? The link doesn't work now

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                            #28

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                              #29
                              A couple of notes about the above schematic. You can likely eliminate the +12v going into pins 8 and 16 with most modern monitors and upscalers. The sense pins usually aren't connected in them. If your CGA card has composite out, you can likely run it directly into pin 20 in lieu of building that circuit that combines H and V sync from pins 8 and 9 of the CGA port. Just keep in mind that some displays and upscalers actually require H+V sync. In that case, you should be able to run those signals directly into the device.

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                                #30
                                Does the above work to any reasonable standard? Might it be worth making a simple PCB for this - SCART sockets are still available (and apparently very cheap).

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