Getting CSYNC from the Neo Geo CDZ

Neo Alec

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I decided to post a topic about this since I was curious, and couldn't find an answer. You have to perform this mod to get CSYNC from the Neo Geo CDZ.

I opened up my CDZ, and confirmed that it has the same issue as the toploader -- composite video is connected to the sync pin on the multi out, rather than CSYNC. You can see that composite video and sync are connected in the photo below:
20180519_225631.png

You can see the same issue for the toploader detailed here:
http://retrorgb.com/ngcdcsync.html

Just like the fix for the toploader, you need to cut the traces connecting sync to composite. Cut in the places marked red:
20180519_231404.png

You have to pull csync from the MB3516A video encoder chip on the other side of the board. Per the data sheet here http://pdf.datasheetcatalog.com/datasheet/FujitsuMicroelectronics/mXrxtqy.pdf pin 10 is CSYNC in. Xian Xi already has this part documented on his site: http://www.jamma-nation-x.com/jammax/images/tuts/cdz-rgb.jpg

Unfortunately, it's a surface mount chip, so you will have to run a wire from the front side of the board to the back:
20180519_233152.png

The sync signal will be too strong and could damage your equipment, so add a 470 ohm resistor (console side) followed by a 220uF capacitor (positive side facing console/resistor, negative side facing sync output to TV) to the wire. Here I've run the wire from pin 10 of the MB3516A to the back side of the motherboard:
20180519_233505.png

And here's the completed mod. Don't forget to add the resistor and capacitor (not shown). You have to reconnect the composite video with a jumper wire, like with the toploader mod:
20180519_233531.png
 
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superfry63

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Well done! - I just did my Toploader the other day. Not too bad but, take your time, check twice before cutting traces, etc all that good stuff.

I am still waiting on my CSYNC Scart/RGB cable, but I wonder what happens if you use the cable without performing this mod....

Does it work but doesn't look as nice?
 

Neo Alec

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Yeah, for the most part composite will work okay for sync. You'll just get a noisier picture. The results can depend on your screen. This is a somewhat elective mod if you're trying to keep your systems stock. In my case, both my NGCD's already had region switches, so they weren't stock anyway.

SNK probably connected it this way because so few people were using RGB outside of PAL or SECAM regions. They probably thought it was good enough, and kept the board layout simpler. Some of the AES models are also connected this way.

For my Framemeister I wasn't seeing it because my SCART > Framemeister adapter already has a sync stripper built-in. Those work fine for isolating the sync signal from composite or S-video. I suspect if I didn't have this then the mod would have been mandatory.

I probably wasn't seeing it on my CRT either because these types of imperfections in the signal are just harder to see on an analog screen.
 
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MKL

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You're doing what Sega did on the Genesis, send TTL csync to the encoder as well as to the A/V port. But the voltage on that sync, being TTL, is too high and should be lowered to 0.3Vpp with a resistor. It should also be possible to replace the encoder with a BH7236AF which has the same pinout as the stock encoder but it does output composite sync from pin 11.
 

Neo Alec

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Thanks MKL. I was wondering about that. I'll add resistors.
 

superfry63

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You're doing what Sega did on the Genesis, send TTL csync to the encoder as well as to the A/V port. But the voltage on that sync, being TTL, is too high and should be lowered to 0.3Vpp with a resistor. It should also be possible to replace the encoder with a BH7236AF which has the same pinout as the stock encoder but it does output composite sync from pin 11.

I'm assuming this applies to the Top Loader as well? I'm just wondering what you mean by TTL and what type of resistor I should use and where to solder it on. (If the voltage is too high will it damage whatever it is outputting to ?)

Thanks in advance,
 

Jumpingmanjim

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I'm assuming this applies to the Top Loader as well? I'm just wondering what you mean by TTL and what type of resistor I should use and where to solder it on. (If the voltage is too high will it damage whatever it is outputting to ?)

Thanks in advance,

TTL means 5v. I'm a bit confused by lowering to 0.3Vpp, I thought the standard was more like 0.7Vpp. Anyway the way it is done on a genesis cable is with a 470 ohm resistor (https://www.retrogamingcables.co.uk/Sega-Mega-Drive-Genesis-CSYNC-output-design-and-analysis). This can be confirmed with a voltage divider calculator (http://www.ohmslawcalculator.com/voltage-divider-calculator).

While we are on the subject of the CDZ, I have heard that it has a lot of problems with heat and will shut down after running for a while, is this true?
 

MKL

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If you're sending sync to a composite video input 0.3v is correct because the sync part of a composite video signal is 0.3v.
 

Neo Alec

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While we are on the subject of the CDZ, I have heard that it has a lot of problems with heat and will shut down after running for a while, is this true?
Removing the bottom metal shielding from the system and not setting it on carpet will fix most of the problem.



If you're sending sync to a composite video input 0.3v is correct because the sync part of a composite video signal is 0.3v.
I'm using RGB through scart though.
 

superfry63

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Removing the bottom metal shielding from the system and not setting it on carpet will fix most of the problem.




I'm using RGB through scart though.

I was just going to ask - Would I need any resistors etc - when everything arrives, I will be using a CSYNC cable (with the mod performed) and it will be going to the OSSC.

Really don't want to fry anything lol
 

Neo Alec

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I added the 470 ohm resistor and a 220uF capacitor to the first post. This is the same configuration commonly used on the Genesis/Mega Drive.
 
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madman

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I'm not fully into this RGB stuff, but I haven't done this mod and my CDZ looks fine, I don't see any video noise or anything. What's the point of this mod? What would this sync give me that I'm not getting now? I'm using the Retro Gaming Cables CD/CDZ cable.
 
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ChuChu Flamingo

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I'm not fully into this RGB stuff, but I haven't done this mod and my CDZ looks fine, I don't see any video noise or anything. What's the point of this mod? What would this sync give me that I'm not getting now? I'm using the Retro Gaming Cables CD/CDZ cable.

Their cables are pretty good. Did you get the fully shielded cable or partial?

From what I've gathered some people's scalers/display devices need CSYNC for them to function properly. Some displays even expect TTL voltage and not 75 ohm terminated (some professional monitors/arcade monitors for example).

For consoles that don't have native CSYNC it means you need to mod or use a sync stripper to extract CSYNC from composite video or luma. The one caveat with using a sync stripper is that the picture will be shifted 5 pixels or so compared to everything else + output at ttl voltage. Just make sure if it is being connected to consumer equipment you put some attenuation at the end of it.

You probably are not noticing a difference because each display masks it better or worse. There really isn't any difference between CSYNC, Sync on luma, sync on composite video with fully shielded scart cables imo. The same cannot be said for non-fully shielded cables.

Tl;dr people usually use CSYNC for compatibility reasons/being able to skimp out on fully shielded cables.
 
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GohanX

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Their cables are pretty good. Did you get the fully shielded cable or partial?

From what I've gathered some people's scalers/display devices need CSYNC for them to function properly. Some displays even expect TTL voltage and not 75 ohm terminated (some professional monitors/arcade monitors for example).

For consoles that don't have native CSYNC it means you need to mod or use a sync stripper to extract CSYNC from composite video or luma. The one caveat with using a sync stripper is that the picture will be shifted 5 pixels or so compared to everything else + output at ttl voltage. Just make sure if it is being connected to consumer equipment you put some attenuation at the end of it.

You probably are not noticing a difference because each display masks it better or worse. There really isn't any difference between CSYNC, Sync on luma, sync on composite video with fully shielded scart cables imo. The same cannot be said for non-fully shielded cables.

Tl;dr people usually use CSYNC for compatibility reasons/being able to skimp out on fully shielded cables.

This is all correct, but I think a lot of the push for csync is retarded noobs who automatically think it's "better" regardless of whether their display needs it or not.
 

FilthyRear

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Their cables are pretty good. Did you get the fully shielded cable or partial?

From what I've gathered some people's scalers/display devices need CSYNC for them to function properly. Some displays even expect TTL voltage and not 75 ohm terminated (some professional monitors/arcade monitors for example).

For consoles that don't have native CSYNC it means you need to mod or use a sync stripper to extract CSYNC from composite video or luma. The one caveat with using a sync stripper is that the picture will be shifted 5 pixels or so compared to everything else + output at ttl voltage. Just make sure if it is being connected to consumer equipment you put some attenuation at the end of it.

You probably are not noticing a difference because each display masks it better or worse. There really isn't any difference between CSYNC, Sync on luma, sync on composite video with fully shielded scart cables imo. The same cannot be said for non-fully shielded cables.

Tl;dr people usually use CSYNC for compatibility reasons/being able to skimp out on fully shielded cables.

Holy shit, why don't all you people play the fucking games instead of worrying about the minutae of video output?

Does it look better to make your youtube videos or something?
 

Tw3ek

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Holy shit, why don't all you people play the fucking games instead of worrying about the minutae of video output?

Does it look better to make your youtube videos or something?

Who the fuck actually PLAYS games?
 

Damulta

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Why hasn't anyone here came up with a mod to play Neo Pocket on the TV?
 

madman

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This is all correct, but I think a lot of the push for csync is retarded noobs who automatically think it's "better" regardless of whether their display needs it or not.

That's what I figured, more RGB faggotry from autists.
 
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