X68000 Monitor to Female RGB 21 Pin Adapter (revised)

[gatsu25]

I need some help.
I tried soldering this today using these two pin-outs.

http://www.gamesx.com/wiki/doku.php?id= ... ese_rgb-21

http://www.gamesx.com/wiki/doku.php?id= ... ese_rgb-15



On the Female 21 Pin I have a Stereo Audio Female lead coming out separate from what is connecting to the Monitor. Like this: http://dempa.jp/rgb/drug/21to15a.html

I took both the V Sync and H Sync which are separate on the 15 pin side and soldered them together on 9 pin on the 21 pin side.

I soldered the Ys from the 15 pin side onto the 16 pin on the 21 pin side. I am a little unsure of this. Should it be connected to the 11 pin instead? Should I have some sort of bridge or resistance there?

I don't have anything leading to the 7 pin on the 21 pin side. I am unsure of this as there is no sync ground on the 15 pin side.

I plugged in my MSX today via a 21 pin RGB to the cable I made. I get colors, but it is just flickering horizontally and I can't really make out a picture. Please take a look and tell me how my wiring is wrong. Feel free to ask questions if my description was difficult to understand or you need more info. Thanks for any help.

[gatsu25]

To be clear, the diagram I made in that picture is the way I wired it up, obviously not how it should be! Anybody have any ideas?

[alamone]

I don't think you can just solder the H and V together, you have to use a circuit or IC to combine the sync.
But if you are wiring the 21 pin direct to your monitor, try connecting only the VSync line and leave H open, it might work.

[Fudoh]

If you use a female JP21 connector on your cable, what do you use to connect this end to your TV set ?

When handling Scart/JP21 connector the pinout changes when you switch from the input to the output side. All pinouts you find online only apply to female inputs, which means you use MALE connectors on your cable.

[gatsu25]

I don't think you can just solder the H and V together, you have to use a circuit or IC to combine the sync.
But if you are wiring the 21 pin direct to your monitor, try connecting only the VSync line and leave H open, it might work.

I will try opening the H Sync first.

If you use a female JP21 connector on your cable, what do you use to connect this end to your TV set ?

When handling Scart/JP21 connector the pinout changes when you switch from the input to the output side. All pinouts you find online only apply to female inputs, which means you use MALE connectors on your cable.

This is basically to connect any JP21 RGB consoles to my X68000 Monitor. Thus, the 15 pin male plugs into the X68K monitor, and the Female RGB 21 Pin is so I can input video from whatever console I want to use.

I don't believe I have the pinouts backwards. In that case, I wouldn't get anything video at all. I'm getting colors at least, just can't make out a picture and is flickering horizontally.

Do I not need to worry about grounding the Sync lines?

[gatsu25]

I just tried unconnecting the H-Sync. It didn't solve my problem. Same exact picture. Also, I tried Changing the Ys from the 16 pin to the 11 pin to see if that made any difference. It's giving me the exact same picture as well... Could it be I need some kind of circuit to combine the H and V sync? What about grounding them? Where can I find info on that?

[Fudoh]

This is basically to connect any JP21 RGB consoles to my X68000 Monitor.

oh I see, I thought it was the other way around.

Could it be I need some kind of circuit to combine the H and V sync?

you don't want to combine H/V, but split C-Sync.

To use C-Sync from a JP21 source on a monitor which requires H/V sync, you need a sync splitter. Without it, it won't work. A simple LM1881 inside the cable should do the trick.

[gatsu25]

Thanks a lot for the help. I'm not exactly sure how I should wire up the LM1881, is there a website or something so I can look for a reference? Also, as far as the Ys. Right now I have it wired into pin 16. Should that be in 11 instead?

[Fudoh]

http://www.gamesx.com/misctech/lm1881.htm

As long as the monitor shows anything and doesn't switch it off by itself, it shouldn't matter if you pin 11 or 16 from the JP21 source.

[gatsu25]

Thanks again. I will try to get materials this weekend.