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To cut a long story short I recently decided to open up an SMS II and add RGB out but I discovered it had one of the surface mount MB3614 encoders.

According to various sources on the internet it is the same operation as the Sony CXA encoder for getting RGB, But to my surprise the picture quality coming from it doesn't look that great.

I know about typical jail bar interference but there appears to be a slight checkered horizontal interference that makes the jailbars go a bit out of shape, is this normal for the MB3614?

Full Size Picture: http://www.imagebam.com/image/94d2f1362507571

I fitted a Mini Din-9 in place of the removed RF Modulator and used a Mega Drive Model 2 RGB Scart.

On a MD this problem comes from blue signal line exiting the VDP being too close to the subcarrier line and shielding the RGB lines all the way to encoder completely fixes it.
I definitely noticed these jailbars on my SMS2 too, but I have not made any attempts to fix them. You also get them with Sony encoder not just the Fujitsu one.
I am also quite certain the problem is same as with MD, though there's whole lot shorter traces and less mess in a SMS around that. I have to experiment with that when I got time.

TmEE wrote

On a MD this problem comes from blue signal line exiting the VDP being too close to the subcarrier line and shielding the RGB lines all the way to encoder completely fixes it.
I definitely noticed these jailbars on my SMS2 too, but I have not made any attempts to fix them. You also get them with Sony encoder not just the Fujitsu one.
I am also quite certain the problem is same as with MD, though there's whole lot shorter traces and less mess in a SMS around that. I have to experiment with that when I got time.

Are the horizontal interference lines present also? they seem to be slightly checkered and cause the vertical jail bars to appear jagged in some bits, most noticeable on the in game shots if you zoom in.

I had the same problem with my sms2.
You can lift the subcarrier pin on the encoder.
Do you use a lcd or led tv?
From what i see, you're from UK. Mod the console to run in 60hz and the jailbars will be gone.
That worked for me.
50hz crt - no jailbars
50hz led tv - jailbars
60hz crt or led tv - no jailbars

Hope it works for you too.

gorgyrip wrote

I had the same problem with my sms2.
You can lift the subcarrier pin on the encoder.
Do you use a lcd or led tv?
From what i see, you're from UK. Mod the console to run in 60hz and the jailbars will be gone.
That worked for me.
50hz crt - no jailbars
50hz led tv - jailbars
60hz crt or led tv - no jailbars

Hope it works for you too.

Yep, I read articles from various forums of members doing a similar technique with the Mega Drive and It does reduce the jail bars significantly, There are still some faint bars on the picture but it is much more acceptable.

I just grounded pin 6 with a wire rather than lifting.

Now I'm trying to get rid of the audio buzz,

I don't think it can be eliminated completely as I've tried taking the audio directly from the SEGA 315-5246 chip isolated from the SCART cable and this does reduce the buzz but not completely.

The only way the audio comes out clean is with the video disconnected so I'm guessing the common ground on the SMS II gets interference from the RGB lines which loops back into the audio ground.

For sound you need to buffer it and also add some extra bypass caps. The stuff coming out the chip is weak and easily picks up distortion. You also want to use shielded wire from the chip to whereever your buffer is.

Author	Message
Whitesnake Joined: 22 Dec 2004 Posts: 43 Location: UK	Master System II RGB from MB3614 Encoder Posted: Wed Nov 05, 2014 10:58 pm
Whitesnake Joined: 22 Dec 2004 Posts: 43 Location: UK	To cut a long story short I recently decided to open up an SMS II and add RGB out but I discovered it had one of the surface mount MB3614 encoders. According to various sources on the internet it is the same operation as the Sony CXA encoder for getting RGB, But to my surprise the picture quality coming from it doesn't look that great. I know about typical jail bar interference but there appears to be a slight checkered horizontal interference that makes the jailbars go a bit out of shape, is this normal for the MB3614? Full Size Picture: http://www.imagebam.com/image/94d2f1362507571 I fitted a Mini Din-9 in place of the removed RF Modulator and used a Mega Drive Model 2 RGB Scart.

TmEE Joined: 31 Oct 2007 Posts: 853 Location: Estonia, Rapla city	Posted: Thu Nov 06, 2014 11:18 am
	On a MD this problem comes from blue signal line exiting the VDP being too close to the subcarrier line and shielding the RGB lines all the way to encoder completely fixes it. I definitely noticed these jailbars on my SMS2 too, but I have not made any attempts to fix them. You also get them with Sony encoder not just the Fujitsu one. I am also quite certain the problem is same as with MD, though there's whole lot shorter traces and less mess in a SMS around that. I have to experiment with that when I got time.

Whitesnake Joined: 22 Dec 2004 Posts: 43 Location: UK	Posted: Thu Nov 06, 2014 11:40 am
Whitesnake Joined: 22 Dec 2004 Posts: 43 Location: UK	TmEE wrote On a MD this problem comes from blue signal line exiting the VDP being too close to the subcarrier line and shielding the RGB lines all the way to encoder completely fixes it. I definitely noticed these jailbars on my SMS2 too, but I have not made any attempts to fix them. You also get them with Sony encoder not just the Fujitsu one. I am also quite certain the problem is same as with MD, though there's whole lot shorter traces and less mess in a SMS around that. I have to experiment with that when I got time. Are the horizontal interference lines present also? they seem to be slightly checkered and cause the vertical jail bars to appear jagged in some bits, most noticeable on the in game shots if you zoom in.

gorgyrip Joined: 11 Mar 2006 Posts: 80	Posted: Sat Nov 08, 2014 9:55 am
gorgyrip Joined: 11 Mar 2006 Posts: 80	I had the same problem with my sms2. You can lift the subcarrier pin on the encoder. Do you use a lcd or led tv? From what i see, you're from UK. Mod the console to run in 60hz and the jailbars will be gone. That worked for me. 50hz crt - no jailbars 50hz led tv - jailbars 60hz crt or led tv - no jailbars Hope it works for you too.

Whitesnake Joined: 22 Dec 2004 Posts: 43 Location: UK	Posted: Mon Nov 10, 2014 12:00 am
Whitesnake Joined: 22 Dec 2004 Posts: 43 Location: UK	gorgyrip wrote I had the same problem with my sms2. You can lift the subcarrier pin on the encoder. Do you use a lcd or led tv? From what i see, you're from UK. Mod the console to run in 60hz and the jailbars will be gone. That worked for me. 50hz crt - no jailbars 50hz led tv - jailbars 60hz crt or led tv - no jailbars Hope it works for you too. Yep, I read articles from various forums of members doing a similar technique with the Mega Drive and It does reduce the jail bars significantly, There are still some faint bars on the picture but it is much more acceptable. I just grounded pin 6 with a wire rather than lifting. Now I'm trying to get rid of the audio buzz, I don't think it can be eliminated completely as I've tried taking the audio directly from the SEGA 315-5246 chip isolated from the SCART cable and this does reduce the buzz but not completely. The only way the audio comes out clean is with the video disconnected so I'm guessing the common ground on the SMS II gets interference from the RGB lines which loops back into the audio ground.

TmEE Joined: 31 Oct 2007 Posts: 853 Location: Estonia, Rapla city	Posted: Mon Nov 10, 2014 7:32 am
	For sound you need to buffer it and also add some extra bypass caps. The stuff coming out the chip is weak and easily picks up distortion. You also want to use shielded wire from the chip to whereever your buffer is.

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