CGA to VGA adapter help

[wildchild22]

I have the cheap ebay scaler. I have hooked up my consoles scart to the RGBs on the gb-8220 I have tried my rgb modded n64, tg-16, snes and none of them will give a stable image. The image is fine for a few secs then jumps and then stabilizes. I have tried adjusting the clamp settings sometimes its good other times its not.

I have tried the component video inputs from my ps2 and the pic is rock solid.
I am getting vertical jumping not horizontal tearing. Any ideas on what it willl take to get it working. (All sources are rock solid on my dvdo duo)


I have built a lm1881 sync extractor and that did not help much if at all.
I measured with a multimeter where the power goes in when it is operating and I get 5.02v so I think I am fine in that regard.

[fagin]

I have the cheap ebay scaler. I have hooked up my consoles scart to the RGBs on the gb-8220 I have tried my rgb modded n64, tg-16, snes and none of them will give a stable image. The image is fine for a few secs then jumps and then stabilizes. I have tried adjusting the clamp settings sometimes its good other times its not.

I have tried the component video inputs from my ps2 and the pic is rock solid.
I am getting vertical jumping not horizontal tearing. Any ideas on what it willl take to get it working. (All sources are rock solid on my dvdo duo)


I have built a lm1881 sync extractor and that did not help much if at all.
I measured with a multimeter where the power goes in when it is operating and I get 5.02v so I think I am fine in that regard.

Common problem is the wiring of your SCART connectors. Lack of required grounds is normally the issue. I had to modify all of my SCART leads to compensate, apart from my PS2 lead, to work correctly. Don't worry these changes have no effect on continuing to use these leads on any other device.

Let's take your SNES SCART lead.....

Remove the SCART shroud and let me know which SCART PINS have wires going to them.

[wildchild22]

All my troublesome consoles are using play-asia scart snes gamecube cables (cheap)

Okay here is the pins that are connected
7 ,11,15

2,4,6,8,16,18,20

there is a resitor between 8-16
pin 4 and 18 tied together

[fagin]

Bridge from 18 to 17.

You have no composite video ground (if your case no proper sync, hence why the picture won't remain stable).

[wildchild22]

I am using a female scart plug hauled out of a switch that was not rgb compatible.
What grounds should I hook up to it?

So far I have

4,5,9,13,17,21 all tied together.


So I really think I have the play asia's cable covered when hooked up.
Even though 18 is not connected. Seeing 18 is not connected on either cable.


Maybe I only need 2 ,17 and 21 and can remove the others.


For the lm-1881 circuit I have the ground of that tied to the power supply's ground maybe I should put the ground for the chip from the scart plug? I would think it the same as all grounds on the boards are tied to the power supply ground.

[fagin]

Apologies.... I was thinking of something else not related to this circuit, with my previous direction.

Have you followed these instructions to the letter:

Ignore pin 7 & 5 on the IC as it is not needed.

Pin 1 on the IC is HSYNC.

Both IC grounds can be connected to the composite ground on the SCART plug (pin 17).

Composite Input is SCART pin 20.

The CGA to VGA scaler has a RGBHV header and loom provided.

Wire the RGB of the header loom to RGB SCART (pins 15,11 & 7).

Wire the HSYNC of the header (grey) to pin 1 on the IC.

Wire the VSYNC of the header (yellow) to pin 3 on the IC.

Wire the GROUND of the header (black) to SCART pin 17.

Wire COMPOSITE SYNC from SCART (pin 20) to the capacitor in-line with pin 2 on the IC.

Wire IC Pin 8 (power) to the positive on the CGA to VGA scaler.

Wire the phono audio breakout to SCART pin 2,4 & 6 (Right, Ground and Left).

[wildchild22]

I think my lm1881 ic is bad. I tried hooking up without the sync cleaner and I get perfect picture for tg-16 so I am thinking I will build another lm1881 circuit and try that. Thanks for the help. At least I know it is wired right seeing I get a pic now! It seems the lm1881 is bad all along causing my woes. Good thing I ordered a few spares.

[wildchild22]

My lm1881 IC was bad. I just built another one wired it the same way and bam perfect picture. Thanks again Fagin.


I hate to say this but the cga scaler looks better with 240p content scaling to 480p then my duo. Maybe my eyes but there is less ringing.

[Fudoh]

I hate to say this but the cga scaler looks better with 240p content scaling to 480p then my duo. Maybe my eyes but there is less ringing.

Without adding scanlines you're definitely right - the ringing on the Duo is unacceptable (it's just like the Edge), but on the other hand the CGA to VGA converter doesn't really handle 240p very well, so depending on the game and the effects used you can end up with quite some nasty deinterlacing artefacts.

[wildchild22]

Yeah it do have some quirks. Didy kong racing on the n64 is not centered during the into till you start playing the game. Everything is shifted downwards instead of being centered. But oncve the game starts its fine.

I think an xrgb-3 will soon be ordered I love the ebay scaler but I Think the xrgb will be for me.

Too bad micomsoft couldn't make dvdo edge equivalent!!