Projects - VGA to SCART Converter

The RGB signals in VGA and the RGB signals found in a SCART connector are electrically compatable, but the sync signals aren't. In VGA the vertical sync and horizontal sync are carried on separate wires, but in SCART they are both combined into a composite sync signal carried along a single wire. This circuit converts the component sync signals into a composite sync compatable with SCART. The red, green and blue signals can be connected through as-is.

NOTE:

Finished Converter

Have a look at the circuit. It does no frequency conversion or scaling, etc. so your graphics card must output a signal at PAL or NTSC specification if your TV is going to have any chance of syncing with it. If you see 2 images side by side then your graphics card is outputting a standard VGA signal and your TV just happens to be syncing with every other sync pulse (the horizontal sync in VGA runs at exactly twice the frequency of PAL). You should also connect pins 5 and 11 on the VGA connector together to tell the PC that there's a colour monitor plugged in.

Using this circuit instead of using a TV output of a graphics card has some advantages:

The following XFree86 modelines should work. PAL is specified to be 768x576 although 800 pixel wide modes are also listed below. Similarly, NTSC is 720x480 but 800 pixel wide modes are listed below too. Use the extra-wide modes at your own risk - they probably won't look too good since the dot pitch of the TV's CRT is probably too large and there is a small chance you could damage the TV.

Modes ending in "pali" run in the usual interlaced PAL mode, "pal-half" modes provide half the vertical resolution so you don't get an interlaced display. Similarly the "ntsci" modelines give you full interlaced NTSC whilest "ntsc-half" is non-interlaced NTSC whith half the vertical resolution.

Modeline "800x576pali" 15.38  800 823 895 984  576 580 583 625 -hsync -vsync interlace
Modeline "800x288pal-half"  15.38  800 823 895 984  288 290 292 313 -hsync -vsync
Modeline "768x576pali" 14.76  768 789 858 944  576 580 583 625 -hsync -vsync interlace
Modeline "768x288pal-half"  14.76  768 789 858 944  288 290 292 313 -hsync -vsync
Modeline "720x576pali" 13.88  720 742 808 888  576 580 583 625 -hsync -vsync interlace
Modeline "720x288pal-half"  13.88  720 742 808 888  288 290 292 313 -hsync -vsync
Modeline "704x576pali" 13.50  704 722 786 864  576 580 583 625 -hsync -vsync interlace
Modeline "704x288pal-half"  13.50  704 722 786 864  288 290 292 313 -hsync -vsync
Modeline "650x576pali" 12.50  650 669 728 800  576 580 583 625 -hsync -vsync interlace
Modeline "800x480ntsci" 15.10  800 808 879 960  480 484 487 525 -hsync -vsync interlace
Modeline "800x240ntsc-half"  15.10  800 808 879 960  240 242 244 263 -hsync -vsync
Modeline "720x480ntsci" 13.59  720 727 791 864  480 484 487 525 -hsync -vsync interlace
Modeline "720x240ntsc-half"  13.59  720 727 791 864  240 242 244 263 -hsync -vsync
Modeline "704x480ntsci" 13.34  704 714 776 848  480 484 487 525 -hsync -vsync interlace
Modeline "704x240ntsc-half"  13.34  704 714 776 848  240 242 244 263 -hsync -vsync
Modeline "657x480ntsci" 12.50  657 667 725 792  480 484 487 525 -hsync -vsync interlace
Modeline "657x240ntsc-half"  12.50  657 667 725 792  240 242 244 263 -hsync -vsync
Modeline "640x480ntsci" 11.32  640 646 703 786  480 484 487 525 -hsync -vsync interlace
Modeline "640x240ntsc-half"  11.32  640 646 703 786  240 242 244 263 -hsync -vsync
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Site last updated: 26th June, 2013