gbs-8200 and Sega genesis model 1 sync

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kynrek
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Joined: Sat Dec 27, 2014 3:00 pm

gbs-8200 and Sega genesis model 1 sync

Post by kynrek »

I have a Sega genesis model 1 and I want to use my gbs-8200 CGA to VGA converter to do an RGB to vga conversion. The board has inputs for RGB sync and ground I know most people use SCART but I was going to make my own 8pin din cable to grab the R G B ground and sync signals from the genesis outputport. With the output from the sync pin work (as opposed to stripping if from the composite video)?

Here is a picture of the gbs-8200 board:

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beatsgo
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Re: gbs-8200 and Sega genesis model 1 sync

Post by beatsgo »

So first things first: welcome to the forum!

The GBS-8200 has the 5pin EGA/CGA port, which as you can see uses R, G, B, GND, and S. Base off of the first Genesis pinout, you'll be connecting pins 7, 4, 8, 2, and 6 to their respected pins. The Genesis already has a C-Sync line, so you don't need to worry about stripping video data from it.
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kynrek
Posts: 47
Joined: Sat Dec 27, 2014 3:00 pm

Re: gbs-8200 and Sega genesis model 1 sync

Post by kynrek »

beatsgo wrote:So first things first: welcome to the forum!

The GBS-8200 has the 5pin EGA/CGA port, which as you can see uses R, G, B, GND, and S. Base off of the first Genesis pinout, you'll be connecting pins 7, 4, 8, 2, and 6 to their respected pins. The Genesis already has a C-Sync line, so you don't need to worry about stripping video data from it.

Great, thanks for the welcome and for your response!

Does anyone know if i will need to "boost" the sync? (It seems to be something that is commonly done)
kynrek
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Re: gbs-8200 and Sega genesis model 1 sync

Post by kynrek »

I happened to have a "project" SNES lying around. I hooked up straight to the RGB and Sync (not composite, but plain sync) from the board to my gbs-8200 and it worked without any extra parts! I am hoping the Sega will work the same way. All I had to do was hold the down button on the gbs-8200 for about 10 seconds and it did an auto adjust and the picture show up perfectly.


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TheRac25
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Re: gbs-8200 and Sega genesis model 1 sync

Post by TheRac25 »

kynrek wrote: Great, thanks for the welcome and for your response!

Does anyone know if i will need to "boost" the sync? (It seems to be something that is commonly done)

actually you need to add a 680 ohm dropper resistor since the gbs max voltage on inputs is 3.6v
kynrek
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Re: gbs-8200 and Sega genesis model 1 sync

Post by kynrek »

TheRac25 wrote:
kynrek wrote: Great, thanks for the welcome and for your response!

Does anyone know if i will need to "boost" the sync? (It seems to be something that is commonly done)

actually you need to add a 680 ohm dropper resistor since the gbs max voltage on inputs is 3.6v
Ok Great, Thanks!
kynrek
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Joined: Sat Dec 27, 2014 3:00 pm

Re: gbs-8200 and Sega genesis model 1 sync

Post by kynrek »

TheRac25 wrote:
kynrek wrote: Great, thanks for the welcome and for your response!

Does anyone know if i will need to "boost" the sync? (It seems to be something that is commonly done)

actually you need to add a 680 ohm dropper resistor since the gbs max voltage on inputs is 3.6v

Ok so without the 680 ohm resistor I get "No signal" but with it the picture is all jumpy seems like the vertical sync is off. I checked and the sync line was still 4.4 volts with the 680 ohm resistor so I added a 220 ohm in right after the 680 and Boom! the video looks great!

Thanks for your help!
kynrek
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Re: gbs-8200 and Sega genesis model 1 sync

Post by kynrek »

The Mod was successful!

Anyone know could be causing the white bleeding on the right of the logo?
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or these faint diagonal waves?

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