Neo Geo CD - Strangest Issue with Video outs

superfry63

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Hi There,

Noob here and apologies in advance for the massive first post, but I like to include what I have done so far as to help pinpoint the issue.

I have a Neo Geo CD top loader and everything works great except the video outs. I only have RCA and an S-video cable to test at this time but here is what happens:

-If I use just the Yellow RCA I get weird interference going up the screen. It's almost like another layer on top of the graphics (which look fine) which just flies up from the bottom of the screen and repeats when it gets to the top.

However, if I plug in the L/R RCA jacks into the same TV - it goes away like 95% (you would really have to sit close and look hard)

But, if you plug the audio in else where, lets say a receiver or something other than that TV, its just as bad as only using the video out RCA.

-The same applies for the S-Video out... As long as the sound is going to the same TV it's fine.

Here is something else I noticed. If I run the S-video into the TV, but the Audio else where, yes it looks bad, but then If I also run the Yellow RCA Video out to that TV on a completely different input (i.e. S Video is on Video 1, and this RCA Video out is plugged into Video 3) It's fine!

Is this some sort of ground issue? I did open up the system and reflow the solder on the RCA and S-Video Grounds, but no improvement. It also seems that the shorter the cables the better.

One other thing I will note is that it is not an original PSU. It's a HDD power supply that does 5v and 12v for 2A each. I checked with a multimeter and the specs are pretty much bang on, but maybe the 12V is too high and needs to be brought down to 10V?

I've tested all this on multiple tv's different RCA and S-Video cables, not sure what to check next.

On a final note, one of the TV's I have really hates being plugged into the same outlet as the power supply and it will add a ton of interference even if you do all the "tricks" I have previous mentioned.

Any suggestions would be greatly appreciated.

Thanks,
 

superfry63

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Update: turned out to be the PSU.

I had ordered a 5v, 10V 2A each power cord from overseas and it showed up today - not original. (wasn't expecting it for quiet a while)

All issues gone - Hopefully someone else with similar issues reads this and doesn't waste as much time as I did.
 

superfry63

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Hey thanks, was driving me nuts.

I'm sure alot of people on here are more interested in the MVS or AES ( I myself only picked up the toploader because it was a good deal) but has anyone ever tried using RGB/Scart out on a Neo Geo CD?

I was reading on Retro RGB about how all models had CSYNC, but it wasn't wired up properly. I performed the mod the other day (cut 2 traces and solder in x2 wires) just waiting on some Cables.
 

Kid Panda

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Yea I use RGB on mine all the time. It's fine. I didn't do anything to it though.
 

superfry63

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Yea I use RGB on mine all the time. It's fine. I didn't do anything to it though.

I get my cables from Robert (RetroGamingCables in the UK) I asked him about it and he did mention he has sold a ton of CSYNC cables for Neo Geo CD and no one has ever complained. I showed him the link (http://retrorgb.com/ngcdcsync.html) and he actually reached out to Rob @ RetroRgb and came back and told me to do the mod.

That's awesome it works without it, I'll post back here and advise if mine looks completely wrecked or if it works.
 

GohanX

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Never tried c sync, but the CD systems generally have the best RGB output of all neo systems.
 

madman

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Never did any mods on my CDZ related to video, as Gohan points out the output is amazing.
 

famicommander

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My Neo Geo CD has better video output that any analog system I've seen.
 

Heinz

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Strangest issue huh? fuckin hell this is some clickbait bullshit ain't it?
 

Neo Alec

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Edit: Nevermind. It seems like Retrorgb is claiming that the sync pin isn't even connected to anything, but if you read the actual mod instructions it makes clear that composite is connected to the sync pin. I'll have to check my systems.
 
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superfry63

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Diving back into this one for a bit.

Not sure if anyone knows the answer to this one, but i've done the mod (it's CSync now) and I finally have a scart cable to try from retrogaming cables.

But all I get is a black screen. Every other video out works and I can get sound NP.

I checked some videos online about checking some of the inductors that look like resistors, but that's usually only the case if all the other video outs are shot too.

Ideas?
 

madman

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So you got a new PSU, everything was fine, you did a csync mod and now RGB doesn't work? Or am I missing something?

Edit: Oh, you only used s-video and composite in the past. You sure the mod isn't botched?
 
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superfry63

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So you got a new PSU, everything was fine, you did a csync mod and now RGB doesn't work? Or am I missing something?

Edit: Oh, you only used s-video and composite in the past. You sure the mod isn't botched?

np - its alot of info.

Pretty much, all video outs work RCA/Composite and S-Video but not the Multi Out/RGB.

But, I never had anything to test with until now.

That was my first guess - I botched the mod, but Im just double checking my work now and I am not seeing any signals going where they are not supposed to, and I can trace the sign signal right to the sync pin on the multi out.

I've got the whole thing apart now, could be the cable. (will check in a sec)
 

madman

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Why did you mod the system before getting the cable? You've introduced another variable for no reason at all.
 

superfry63

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Why did you mod the system before getting the cable? You've introduced another variable for no reason at all.

1 - I'm an impatient sob

2 - its super easy to roll back.

3 - I like playing with soldering irons

But I don't deny you raise a very valid point lol
 

superfry63

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So a recap of where I have left this:

-Tried with the CSYNC Mod, with no 470ohm resistor = nothing from the OSSC
-Tried with the CSYNC Mod, a 470ohm resistor = nothing from the OSSC
-Rolled back the mod = Nothing

I'm guessing at this point it's the cable or maybe the AV port?
 

Neo Alec

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Sounds like a trace is broken or maybe something's bridged. Check continuity with a multimeter.

I hate "playing with soldering irons." If you attempt a mod and you are inexperienced, it's very easy to break something. Learned that many times the hard way.
 
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GohanX

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Did you try composite video sync before using csync? Csync isn't necessarily better, the mod isn't necessary in most peoples' setups.
 

superfry63

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@ NeoAlec

For sure, I've been doing stuff like this for a few years. When I started I took a bunch of broken VCRs and just spent days desoldering and resoldering stuff until I felt comfortable doing any retro gaming stuff. I have a decent Weller soldering station and not trying to boast my "skills" or anything but x2 tiny cuts and soldering a wire with a resistor seemed like an easy way to go and roll back if needed. (not sure about the CDZ, but on the toploader there is a ton of room on that
board)

Microsoldering/Small SMD work on the other hand - I would never even try that at this stage because I know I would just destroy everything lol I've been practicing on already broken boards, but not comfortable with any stuff I care about yet.

I'll see if I can post some pics of the board when I get home. Continuity is okay from the CSYNC that I wired up and the cut traces are not leaking over where they had once been connected.

@Gohanx


Nah, I ended up prepping the board for the incoming Scart cable at the time. Though I did just roll it back to composite video sync with some wires and still nothing coming out of that port.

Agree that either would be fine and the differences would be minimal - Just seemed like an easy mod, but my guess so far is that it wouldn't of worked before the mod either.

I guess I could try grabbing the Sync from the S-video Luma pin next.... what throws me off is that I was at least expecting some kind of terrible video output coming through VS nothing at all lol


I actually found a replacement board for 20$ that the seller had listed as "working" as is the same "NEO-CDA3-1" revision that I have. Won't be in for 2 weeks but nice to know for a backup. Also I have a "AV out to White RCA and Yellow RCA" inbound that I can use to see if the port works at all, excluding RGB/Sync. Dirt cheap and can help rule out some stuff :)

As always thanks for the replies.
 
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