FishFinger
Experienced Member
This is something I made the other day, and I thought people here might find it handy. It's a little adaptor that lets you connect a CGA card to the SCART socket on a TV.
Many CGA cards already have a composite output, but the quality is often dubious at best, and they all use NTSC colour, which may not be supported by your TV if you live outside the US.
(click for big)
It uses a few resistors to convert the TTL RGBI signals down to 0.7V RGB, and a circuit based on this VGA-SCART adaptor, which uses a 74HC86 (quad XOR) to generate a composite sync signal from the CGA's seperate HSYNC and VSYNC.
As well as connecting to the CGA port it also needs +5V and +12V, which aren't available on the CGA connector, so it needs a molex connector for plugging into the PSU. (I left this off the diagram for clarity).
NOTE:
- Although SCART itself has pins for RGB input it may not be supported on all TVs - mostly only very old, or very cheap/crappy ones though.
- Some TVs with multiple SCARTs may only support RGB on one of them.
- The display is still 60Hz, so your TV must support that too (all TVs in the US do, and most non-US TVs made in the last 15 years or so should as well)
Many CGA cards already have a composite output, but the quality is often dubious at best, and they all use NTSC colour, which may not be supported by your TV if you live outside the US.
(click for big)
It uses a few resistors to convert the TTL RGBI signals down to 0.7V RGB, and a circuit based on this VGA-SCART adaptor, which uses a 74HC86 (quad XOR) to generate a composite sync signal from the CGA's seperate HSYNC and VSYNC.
As well as connecting to the CGA port it also needs +5V and +12V, which aren't available on the CGA connector, so it needs a molex connector for plugging into the PSU. (I left this off the diagram for clarity).
NOTE:
- Although SCART itself has pins for RGB input it may not be supported on all TVs - mostly only very old, or very cheap/crappy ones though.
- Some TVs with multiple SCARTs may only support RGB on one of them.
- The display is still 60Hz, so your TV must support that too (all TVs in the US do, and most non-US TVs made in the last 15 years or so should as well)
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