Genesis model 2 to 1084s bad video signal

[whoozwah]

I am running an NTSC-U model 2 SEGA Genesis-->RGB scart (cable is supposedly true rgb and not just scart carrying composite)-->this cable-->Amiga 1084s-D1.

When I turn everything on I get this

Any ideas?

Thanks in advance

[SharkSkin-Man]

The RGB scart will probably be wired to use composite video for sync, which the 1084 doesn't like.

An LM1881 will probably solve the problem.

[whoozwah]

okay. I did some reading and heard about that thing. It's a chip that sends individual hsync/vsync signals right?

Where would I put that and more importantly, how? I am a novice with electronics and circuits and such.

Thanks.

[whoozwah]

I tried something. I took an ethernet cable, stripped it and ran all the corresponding wires directly from the female plug on the back of the genesis to the female plug on the back of the monitor. I twisted 2 wires together and put them both into pin 5 (composite sync) and then plugged them into pins 8 and 9 (hsync and vsync) on the monitor. It's a stable picture for about 1 second then the screen fades completely out and I'm left with a blank screen.

What to do?

[SharkSkin-Man]

I thought these monitors didn't require seperate H&V sync in analogue mode? Pin 7 should be composite sync.

[whoozwah]

just tried running a single wire from composite sync to composite sync. It does the same thing. It shows up nice for 1 second then fades out.

[Zapf]

The sega genesis doesn't do composite sync by default (it has a spot on the cable, but its not wired up inside the console), only composite video. As mentioned before, maybe you using composite video is your problem? You haven't mentioned that you actually hooked that back up, so I am thinking you are still using composite video. There are a few guides for wiring that up, I can't find them at the moment though =(

[Fudoh]

It really shouldn't matter. From my past experience (20 years ago), the 1084S should take composite video just as well.

The MD/Genesis (1&2) outputs both, composite video and composite sync. To use the sync line (just check the pinout at gamesx.com) you have to put a capacitor in line.

As long as you don't check the converter with another RGB source or the MD RGB cable on another display, it's still hard to say which part of the cabling is at fault.

[antron]

To use the sync line (just check the pinout at gamesx.com) you have to put a capacitor in line.

I haven't heard this before. Maybe that explains why mine doesn't work on all arcade monitors. What value?

[whoozwah]

the genesis scart cable works fine. I've used it on another display.

[Fudoh]

haven't heard this before. Maybe that explains why mine doesn't work on all arcade monitors. What value?

anything between 100 and 220 uF should work fine.

[whoozwah]

I did some more playing with running loose wires from the genesis female din to the monitor's female 9pin rgb. I found a combination that works and I have a stable, beautiful picture (without needing to add capacitors or a sync stripper or any of that stuff). Turns out it works when you run from pin 5 (comp sync) on the genesis to pin 9 (vsync) on the 1080s-d1.

The only problem I have at this point (since I have a proper pinout I can use that works for making a working cable) is I don't know how to resolve the issue of no sound. How do I wire it up for sound?

[Fudoh]

Turns out it works when you run from pin 5 (comp sync) on the genesis to pin 9 (vsync) on the 1080s-d1.

now that's weird, especially since Pin 9 on the monitor's connector should actually not do anything when in analogue RGB mode...
Does Composite video from the MD/Gen to Pin 9 of the monitor work as well ??

How do I wire it up for sound?

the monitor adapter you've bought has audio connections which go into the monitor's audio inputs. You can still use the adapter. Just resolder the sync pin to pin 9.

On the Mega drive side you can either built a new Scart cable (the Mini Din connector on the MD/Gen2 side is available on eBay). As long as the scart end has audio it will be passed through the monitor adapter. The other way would be using the existing scart cable. You could open up the machine, kill the Composite video pin and solder the composite sync output to the video pin. This way you don't even have to change anything on the MD/Gen cable.

[whoozwah]

now that's weird, especially since Pin 9 on the monitor's connector should actually not do anything when in analogue RGB mode...
Does Composite video from the MD/Gen to Pin 9 of the monitor work as well ??

I tried that and it gave me the same garbage signal that I started out with. Pin it back to composite sync and it works like a champ.

the monitor adapter you've bought has audio connections which go into the monitor's audio inputs. You can still use the adapter. Just resolder the sync pin to pin 9.

This will work out tasty then as the db9 housing just clips open and shut for easy access.

You could open up the machine, kill the Composite video pin and solder the composite sync output to the video pin. This way you don't even have to change anything on the MD/Gen cable.

The end of my scart cable breaks apart to get to the insides. I found a wiring guide for a genny scart cable and I made a pinout based on the colors of the corresponding wires. I bought a 9 pin mini din off ebay which should be here next week. I'll wire that up and fix the wire inside of my adapter cable I bought and I should be good to go.

I've been playing it without sound using just the loose wires connected and it's absolutely beautiful. I've never ever seen the Genesis look so good. After doing that I kinda had a realization. I now know what proper scanlines are supposed to look like. (and that I want all my applicable systems to run through RGB now).

[Turrican]

I am running an NTSC-U model 2 SEGA Genesis-->RGB scart (cable is supposedly true rgb and not just scart carrying composite)-->this cable-->Amiga 1084s-D1.

I am about to buy the same adaptor, but I have an European Megadrive Model 1 and two 1084s (P2 and D2). Should I do the same thing?