Issues with CMVS Slim and SCART rgb

[venchia3]

Dear all,
I'm writing here because I recently bought an Analogue Interactive CMVS Slim + their official SCART rgb cable. Initially I was having some scrolling rainbow effect problems and picture looked absolutely horrible on both my HDTVs (LG and Panasonic ones). With the help of the community at neo-geo.com I discovered that the main problem was the missing resistor on the blanking pin of the rgb cable.

Now, after adding the resistor both of my HDTVs shows a much better video output really close to what RGB should look like. Right now I just have another issue, that is sort of wavy jail bars on specific colours such as reds, blues and greens. I will attach a video I've made yesterday, the jail bars effect can be seen over the SNK logo and the Metal Slug logos:

http://youtu.be/gFeyh3z8DBA

My guess is, since I'm not using any sort of upscan converter like the XRGB, and no other sync cleaner at all, would this issue be related to the missing sync cleaner? I actually can't test the CMVS over a CRT, all I have are my hdtvs. I would really be interested to know your opinions

Thanks for stopping by

[venchia3]

no one has a clue? same effect also with S-Video, just tried 2 days ago. If I use S-Video with an iScan Pro, and sharpness set to normal the jailbars kinda disappear, but when turning up the sharpness jailbars appears...mmmh

[Fudoh]

What's weird about it, is that the stripes are moving. This implies some kind of interference or shielding problem. If you got static jailbars, I would have said it's a problem with a composite video signal (for sync). The use of a video encoder board on the CMVS is what has bothered me from the beginning.

I would usually recommend to just bypass the encoder and take RGBs directly from the MVS board. If the problem remains, it could be a bad power supply (causing heavy interference).

[Pasky]

Using a switching regulator? Looks like switching noise.

[venchia3]

Thank you both so much for the replies! I was wondering myself if the problem was the power supply...I'm not expert but it doesn't seem as an hard to find power supply, so maybe I will try to buy another one, here you are a picture of it



Pasky, sorry for my ignorance, what is a switching regulator, exactly?

I will also have to add the fact that those moving jail bars sometimes stops and stay put for some minutes, then again they start to roll

[Pasky]

In a nut shell:
Switching regulator uses a bunch of components but mainly an inductor to regulate the voltage. Benefits are efficient powering, but the drawbacks are you get switching noise and more power rippling.

A linear regulator regulates the voltage and dissipates everything else as heat.

You can buy a universal linear regulator. Any DC 1.0A+, 5V power supply for a MVS would be good.

EDIT:

Something like this would do the trick, just set it to 5V.

http://www.radioshack.com/product/index ... Id=3875403

It's regulated, and filtered.

You get a free plug when you buy from radioshack also. It's a bit expensive, but it's a quality adapter. Not sure what other good regulated universals there are. Just make sure you don't get some cheap chinese adapter.

Make sure you put the polarity correct on the tip. It would depend how you have your power jack wired.

[venchia3]

thank you once again unfortunately I cannot buy from the website you told me, but at least I know what to look like here in Italy. Was thinking, would be a good idea buying also something like this?

http://www.amazon.co.uk/APC-SurgeArrest ... ywords=apc

not here but in Amazon Italy it says it's also filtered

[Ed Oscuro]

Kind of unconvinced about the switch mode power supply criticism - there are plenty of switchmode supplies used for all kinds of frequency-sensitive applications out there. Maybe it's a matter of changing the switching frequency (i.e., as suggested in an old post here, at #5)? Or, more simply, to just use capacitors intelligently to reduce ripple and noise.

Linear power supplies will be an easy solution but, to generalize again, they're inefficient and have to disperse a not insignificant amount of power.

Naturally the original Neo Geo MVS power supply would be switch-mode as well.

Interested to hear more about these design considerations, if anybody has the info...I know we've got one or two power supply designers on board!

[venchia3]

Some updates!
Ok, I finally got my XRGB Mini and did some tests. Since I'm waiting for the euro rgb-MiniDin adapter I used the S-Video connection to try everything out.

Before the XRGB mini I tried the CMVS with another PSU, but no luck, everything worked the same with RGB or S-Video. When I plugged the XRGB mini, after the initial configuration, the image with S-Video was reaaaally good and a big improvement concerning my problem (not only improved the problem, also the overall image quality, but I'm sure there is no need to tell you that ). The image improved by 90%, still I can see a bit of waviness in some background, quite faint to be honest, and maybe because I'm on S-Video...what I found really strange is that, when I use the FREEZE option of the framemeister...the image is rock solid and any waviness gone! maybe I'm wrong but...the waviness shouldn't be present even with the freeze mode on if it is a nasty video disturb?

EDIT: need to add that, as of now, the only game I have for the CMVS is Metal Slug...I don't know if it's something that can be related to the game but I wanted to add this detail

[Fudoh]

the image is rock solid and any waviness gone!

that's to be expected.

I don't know if it's something that can be related to the game but I wanted to add this detail

no. I got a MVS connected to my Mini and the MVS on it's own delivers a *perfect* RGB image. There's absolutely no interference or anything else, so it's most likely the encoder stage in the CMVS to be blamed.

[venchia3]

the image is rock solid and any waviness gone!

that's to be expected.

I don't know if it's something that can be related to the game but I wanted to add this detail

no. I got a MVS connected to my Mini and the MVS on it's own delivers a *perfect* RGB image. There's absolutely no interference or anything else, so it's most likely the encoder stage in the CMVS to be blamed.

Thank you so much! Well it really means my CMVS has something wrong with it...at this point I don't really know if it's worth sending the unit back to the USA to have the encoder replaced with the risk of having the same kind of effect...mmmh dilemma! Do you think it would be better to just modify the unit myself to bypass the encoder and get pure RGB out of the MVS board? I don't really need component or S-Video out of a Neo Geo having a mini and in general living in Europe

[Fudoh]

Do you think it would be better to just modify the unit myself to bypass the encoder and get pure RGB out of the MVS board?

definitely. It's very easy. I never understood why Christoph didn't offer "raw RGB" units as well. Nobody in Europe uses composite, s-video or component on a MVS.

[Bunk]

Did you get any closer to solving your problem venchia3?

I recently bought an Analogue CMVS Slim and get the same picture problem with RGB SCART (hooked up to a Sony Trinitron).

[venchia3]

Did you get any closer to solving your problem venchia3?

I recently bought an Analogue CMVS Slim and get the same picture problem with RGB SCART (hooked up to a Sony Trinitron).

Unfortunately I had to send the unit back to Analogue Interactive, and the seller from where I bought the CMVS slim refunded me. When I know from AI what was the problem I will gladly tell you, but in my opinion just drop an email to Christoph from Analogue Interactive before you try to open up the unit, it's really almost impossible to do it properly by yourself

[Bunk]

Okay, I hope you get a result there. Yes, please do share whatever you find out. That would be much appreciated.

I'd email Christoph myself but I bought the bundle second-hand. Here's hoping there's a fix out there.

[venchia3]

Okay, I hope you get a result there. Yes, please do share whatever you find out. That would be much appreciated.

I'd email Christoph myself but I bought the bundle second-hand. Here's hoping there's a fix out there.

I bought second hand aswell, but if your unit is still under warranty (mine was because the seller gave the unit to me after just 1 week of usage eheh), Christoph will certanly help you out.

I do think it's a pretty annoying issue, I feel it for you too, man...

[Christoph]

Hey guys - I did not see this thread until it was just pointed over to me this morning.

To clarify about the encoder and RGB on the CMVS Slim (it is a Neobitz): RGB is pulled directly from the MV1C motherboard and other than 75ohm resistors on the R, G & B lines, it is raw and untouched.

In regards to the jail bars, this is a strange issue - I'll be sure to post back when we pinpoint the problem and find a solution.

[Fudoh]

RGB is pulled directly from the MV1C motherboard and other than 75ohm resistors on the R, G & B lines, it is raw and untouched.

but if you split the RGB lines and run them a) directly to the RGB output and b) into the component encoder, isn't that basically screwing with the signal impendence, since you're adding a whole circuit parallel to the original signal ?

I've heard from another Mini user that RGB from his CMVS didn't work (but component did). RGB from "standard consolized" MVS boards usually works just fine on the Mini.

[Christoph]

I wouldn't think so since it's an isolated issue, but I can certainly get some more details from the original designer of the NeoBitz. I know a ton of customers use RGB with their XRGB units with no problems (myself included).

I have a system with the jailbar issue on hand right now and I'll post back as soon as I figure out with the issue was!

[Bunk]

Thanks for looking into it Chris. Much appreciated.

[airs]

Not sure if the Analogue unit and the Omega have anything in common for their video output stage but RGB scart works perfectly with my XRGB Mini + Omega CMVS + Omega SCART cable + Retro Console Accessories female SCART to XRGB Mini Din 8 cable. It is the version with the LM1881 though. I can test to see what it does without the LM1881 if that's helpful?

[Christoph]

No problem Bunk - I'll look into it ASAP. I'll shoot you an email for a couple things to test in the meantime.

@airs - that would be worthwhile to test if you were willing to!

My initial hunch is that it's TV related. If so, the LM1881 would likely be the solution.

[panzeroceania]

MV1C MVS units are strictly mono sound only right? I'm surprised a stereo MVS unit wasn't used as the base for the CMVS Slim

[Christoph]

The CMVS Slim does output stereo. You are correct though about the MV1C. You can only pull Mono from the JAMMA edge, but with a modification on board, you can output stereo - which is exactly what the CMVS Slim does.

[panzeroceania]

I see, thank you for clarifying that, I can't wait to hear more about your analogue Nt, you guys make great products