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pacoarcade

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Hello, I bought this Supergun for cheap (23 euro) to connect jamma boards to SCART tv sets and apparently it works fine, but it doesn't buffer the video signal and it drives TTL CSYNC, so I've added a 470 ohm resistor to the CSYNC line and a buffer circuit using THS7314 (next time I'll use THS7374 with filter disabled). I like that it works with Sega 6 buttons controllers, reducing the initial cost to get this running 8o

My setup is simple: I use the R G B pots as voltage dividers to drive the right signal directly to the THS7314. In the outputs I add a 75 ohm resistor in series for each line. I also put a ceramic 100nf capacitor in the THS7314 between Vs and GND, and also a 33uf electrolytic capacitor that removes ghosting.

I attach the latest revision of this circuit.

arcade-scart-video-driver.png
 
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After reading more information, I've switched to AC Coupled THS7374, buffering the Csync signal too. Since some boards give +5V and others 3.5V, along with 100nf ceramic capacitor in the input I've used a voltage divider with a 5k6 and 1k2 that gives the correct voltage in my tests.

Updated circuit in the first post.
 
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I would shift sync to input 1.

Looks good otherwise.
 
Thanks so much.

What would be the advantage? Could you elaborate, please? I'm genuinely interested in understanding this.
 
I don't think it will make any difference. Looking at the datasheet each channel is handled identically. I'm just going by the datasheet which specifies channel 1 as composite video, channel 2 as R, 3 as G, 4 as B in their example circuits.
 
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