Michael Jackson Moonwalker/System 18 video problem

[segasonicfan]

I got me a Michael Jackson's Moonwalker PCB (lol) but to my disappointment it has some screwy ass video output. I've tried it with RGB, S-Video, and Composite out and the result is the same: Super high contrast image with overly-bright coloring. Adjusting the RGB via pots does no good, it has some weird color bleeding effect. Keep in mind this is the ONLY game with this problem so I know my Supergun is fine.

I tried some things to fix it and came up with some interesting findings. When I remove ground from the video line I found the colors were fixed (??) but of course the video is ungrounded and thus wobbly (and only working in RGB of course since the encoder needs ground for power). Seeing this, I added a 500ohm VR to adjust the resistance to ground. This had moderate success as the colors were correct and the image wasn't so wobbly, but there was still some strange bleeding and low resolution effects going on. So I added a non-polarized cap in parallel and that fixed most of it, now there's proper colors with some slight bleeding but a sharp, stable image.

This is some of the screwiest video I've seen so I just have 2 questions:

1) is something wrong with my board or is this normal for a System 18 game/Moonwalker?

2) anyone have any other recommendations for improving the video output?

Toddy and MKL, you knowledgeable crazy peeps could help me I'm sure...

-Segasonicfan

 

[segasonicfan]

UPDATE: Using a VR between the grounds and as well as a 47uf non polar cap between gave me perfect video

Sadly, this will only work with my RGB monitor :/

Any alternate fix suggestions?

-Segasonicfan

 

[ttooddddyy]

I have 4 of these and have not experienced any problems like this.

Sounds like a video ground issue, does it help if you ground pin 14 (video ground) or try running a seperate ground wire from the mobo to the monitor.

 

[segasonicfan]

I have 4 of these and have not experienced any problems like this.

Crap, that's not good news, that means I have a broken board then

Sounds like a video ground issue, does it help if you ground pin 14 (video ground) or try running a seperate ground wire from the mobo to the monitor.

Yeah, I've tried all that, and filtering pin 14 is what gave me the moderately successful output for my one RGB monitor. but if it's a problem with my board it looks like I should be looking at finding the problem with the game rather than tweaking my Supergun :/

I love this game, man this sucks :'(

Thanks for the info so far toddy

-Segasonicfan

 

[lowlight]

Crap, that's not good news, that means I have a broken board then

-Segasonicfan

I know this is kind of resolved, but I have the same board as well and I'm inclined to believe that your's isn't functioning correctly. If it's any consoloation to you, I've noticed that System-18 and System-32 boards seem to have an odd sync issue when it comes to video and power. So, the SG you made should be fine, as Moonwalker should run correctly using S-video board I believe you have sin ceI think I have the same in my SG.

 

[segasonicfan]

I know this is kind of resolved

It's really not resolved at all, so thank you for posting It's very important to me to have a fully working board rather than a partial sucky mod trying to pull decent video from it that only works in one format.

The S-video encoder I'm using is pretty standard (CXA1645) so if your boards work with that then there is definitely something wrong with mine.

I traced the RGB lines to the (predicted) 74LS245 logic IC. I might try replacing that as well as the larger caps to hopefully fix the grounding issue...

-Segasonicfan

 

[lowlight]

Clarification

It's very important to me to have a fully working board rather than a partial sucky mod trying to pull decent video from it that only works in one format.

Believe me, I completely understand...

The S-video encoder I'm using is pretty standard (CXA1645) so if your boards work with that then there is definitely something wrong with mine.

-Segasonicfan

Yeah about that, I should clarify by saying that the S-Video board I'm using is the J-ROK S-Vid/Component board, so if that's the same chipset you've mentioned, then you'd be correct. On a side note, while both board types coin up and operate correctly with this and a Multi syncing powersupply (-5, +5, +12V), System-18 boards cannot coin up at all (without some sort of board modification, I assume) nor can System-32 boards properly sync video in a Taito AWSD cab (possibly due to the fact that there is no -5V in the cab). Granted, that's unrelated to your issue (my own personal problem), but it is something that I recently noticed considering that I once assumed the JAMMA output was the same for these boards after version 16. Thankfully I only have Moonwalker, Golden Axe: Revenge of Death Adder and Spider-Man. I certainly hope you do end up resolving your problem!

- Lowlight

 

[Murray]

I know it doesn't add much to what's been said already, but I have a Shadow Dancer board (also System 18) that positively won't work with my NeoBitz-S encoder (AD724+LM1881) but works fine with the JROK (with the adjustment pots turned way down), so there may be some sync issues.

It could be that your TV is having problems with the sync even though you're using one of the more compatible encoder ICs.

 

[segasonicfan]

Thanks for the support guys. I'll add a few things to clarify:

The JROK uses a CXA2075 from what I've heard- almost exactly the same circuit as the CXA1645 which means my 1645 in my supergun should work with it.

I'm using a ISL59885 sync splitter as well, which is an advanced brand new version of the 1881.

I have tried the game on 3 different TV's I have: My RGB monitor, and 2 norm TV's using S-Video and Composite.

I still get the same problem. And what's really strange is when I use Composite or S-Video it's way worse, there's almost a sort of color glitching going on i.e. on the Sega logo on the splash screen theres a chunk of green bleeding into it

What you said abou turing the pots down makes sense- on the Spiderman board I use to have that's all I had to do to compensate for the high contrast. It seems Sega just didn't decide to use the 75 ohm terminated standard for RGB signals.

However, when I adjust the pots with Moonwalker it goes nuts- the resolution decreases drastically, colors bleed into each other, etc etc :/

Can anyone tell me what the resistance across the +5v and ground inputs is supposed to be? I got 160ohms which seemed damn low to me....

-Segasonicfan

 

[ttooddddyy]

Can anyone tell me what the resistance across the +5v and ground inputs is supposed to be? I got 160ohms which seemed damn low to me....

-Segasonicfan

I checked a couple of my moonwalker boards and they measure around 200 ohms from 5 volts to ground.

This is a red herring though, I dont think this has anything to do with the problem you have.

 

[lowlight]

*SLAPS FOREHEAD*!!

Doh! I just remembered something, check your DIP settings on the second switch (7 or 8, I think). I can't recall exactly, but I believe that the manual had said that one of these two DIP's are either usually set to "OFF" or "ON' by default for the sae of either screen flip or some other unused setting. I remember when I first got my Moonwalker board that toggling one of these two jumpers completely killed my Video Output, in fact, I think I had confused it for the jumper for setting Demo/Attract-Sound. If you haven't already, try that out too.

 

[segasonicfan]

Doh! I just remembered something, check your DIP settings on the second switch (7 or 8, I think). I can't recall exactly, but I believe that the manual had said that one of these two DIP's are either usually set to "OFF" or "ON' by default for the sae of either screen flip or some other unused setting. I remember when I first got my Moonwalker board that toggling one of these two jumpers completely killed my Video Output, in fact, I think I had confused it for the jumper for setting Demo/Attract-Sound. If you haven't already, try that out too.

Tried that I checked the DIP settings online too as you can see here: http://www.coinop.org/kb_dl.aspx/KB/pinouts/moonwalker.txt

None of the DIPs have anything to do with video

The seller of the board has agreed to let me return it but of course I want to have this game and I'd like to test them side-by-side. Anyone have an extra board they would sell/trade me? Also, if anyone has the manual I can't find it online and I think it might have some helpful schematics...

-Segasonicfan

 

[lowlight]

Hmmm

Tried that I checked the DIP settings online too as you can see here: http://www.coinop.org/kb_dl.aspx/KB/pinouts/moonwalker.txt

I see, based on your DIP-Sheet, the jumper I messed with was Bank1-DIP8, the one that's supposed to be always set to "Always OFF". I found that the only way that my video output will work correctly is to have it set to "ON" instead...I tried it again just to be sure this is still the case despite it being in a JAMMA cabinet now, and it seems to be so.

Also, if anyone has the manual I can't find it online and I think it might have some helpful schematics...

-Segasonicfan

Check your PM inbox for this...

 

[Xian Xi]

Here's a question, how many amps does the board require? Most boards average about 4A BUT some PCBs require 7A or more.

 

[segasonicfan]

I see, based on your DIP-Sheet, the jumper I messed with was Bank1-DIP8, the one that's supposed to be always set to "Always OFF". I found that the only way that my video output will work correctly is to have it set to "ON" instead...I tried it again just to be sure this is still the case despite it being in a JAMMA cabinet now, and it seems to be so.

How very strange, your board must have some slight malfuntion too DIP 8 on bnak one is just used for setting the coin/credit mode and has nothing to do with video...it takes absolutely no effect on my board in "on" or "off" position.

Here's a question, how many amps does the board require? Most boards average about 4A BUT some PCBs require 7A or more.

It draws ~2.6 amps. I have yet to come across a board that draws anything over the 4A my Supergun supplies. The MV-1 for example is supposed to draw 5V @ 7A according to its manual. It doesn't draw anything close to that though.

-Segasonicfan

 

[Xian Xi]

My perfect billiards PCB draws 6A.

 

[segasonicfan]

My perfect billiards PCB draws 6A.

I never said all PCBs in the world draw under 4A, I just haven't come across that draws more. Good to know which ones out there do draw more and it makes sense that older games such as Perfect Billiards would.

I traced the RGB lines using a continuity check and they actually lead to their own transistor- C945. I checked all 3 which appear to be worked and I assume these are used to amplify the signal. Before these the signal comes from a PC74HC4066P circuit which I doubt is broken since it's just a standard logic chip. I'm going to try pulling the RGB before the transistor amps and see what happens..

-Segasonicfan

 

[ttooddddyy]

Here is an interesting thread, not directly related but involves the RGB output stage of boardsets (this is for mvs but the same applies)

http://www.neo-geo.com/forums/showthread.php?t=78595

 

[ttooddddyy]

OK after reading that old thread, I now have a theory.

A ceramic resistor array on the RGB output from the board has been damaged in transit (the red 9 pin in line devices, they are 8 x 1 or 10K ohms), as they do. They crack easily, rendering them open circuit.. It could well be on the ground side .

Check RA 17, 18 and 19 near the jamma edge connect. Also behind the two flip flop ICs there are two more resistor arrays, forget the numbers now but they look the same.

Is there a noticable grey scale issue, like too red , green or blue ?

 

[segasonicfan]

Hey Toddy, thanks for the help...

I checked the resistor SIPs, none of them are cracked or damaged :/ There is a gray scale issue if adjust the pots to a low impedence but with everything turned up it looks fine.

On the other side of things I made some possible "progress" with those NPN transistors. I pulled the RGB from before the NPN's and the colors/brightness were correct!! Only two strange things:

1) brightness oscillates slightly and somewhat sparatically in parts
2) the colors for the children you save don't show until after you save them (they are all solid black/very dark)?!?!? -This one baffled me.

So the NPN's must do a little more than amplify the signal somehow they are adding colors to certain sprites, very strange. The transistors also aren't bad, according to the diode test on my multimeter anyway...

There are some caps around the transistors that I haven't replaced yet, anybody think I should replace those? The diodes around the transistors are fine too and I highly doubt the 74HC4066 is damaged :/ How very confusing. One important thing to note however, the vidoe was WAY better when drawn from before the NPN's and even worked with my S-Video encoder! When doing that there was a lot of noise though and also some occasional flickers (almost like a rolling image). Very occasional though.

-Segasonicfan

 

[ttooddddyy]

Toddy (or anyone else) have any ideas on the Moonwalker fix? I removed all the large coupling caps in hope that one of those was bad...but none of them were so I gotta put them back, doh.

You could remove all those caps from a boardset and it would work 100% it is called over design. It is an industry

Edit: apart from some in the audio output stage feedback and reset for the cpu.

 

[ttooddddyy]

So the NPN's must do a little more than amplify the signal somehow they are adding colors to certain sprites, very strange. The transistors also aren't bad, according to the diode test on my multimeter anyway...

I do not remeber these, they are probably emitter follower buffers not voltage amplifiers. Will take a closer look tomorrow.

 

[segasonicfan]

Yeah Toddy, let me know on those transistors- they are on the middle right hand side of the bottom PCB.

Just a quick important thing to note: the noise I experienced from my S-Video connection was a broken S-video cable as it turns out. The grounding pins under the Y & C inputs were pushed into the plug

So I think it's safe to say that the pre-NPN RGB is significantly better. Proper colors, resolution, and contrast. Most importantly, it works with the video encoder. Only two small problems to figure out then, 1) why are the children sprites dark when connecting the pre-NPN RGB and why is there a *slight* contrast flicker in some parts?

Thanks for the help guys! I'm trying to find another board right now but it's tough to track these down. I really love this game....cause....well....I'm a big Michael Jackson fan

-Segasonicfan

 

[lowlight]

...

Thanks for the help guys! I'm trying to find another board right now but it's tough to track these down. I really love this game....cause....well....I'm a big Michael Jackson fan

-Segasonicfan

Check your inbox again...

- Lowlight

 

[jrok]

I really love this game....cause....well....I'm a big Michael Jackson fan -Segasonicfan

Following this thread's been a Thriller, I would have gotten fed up with the board going Bad, put it on the floor and Beat It with a stick... well that's just Human nature....

I'll go away and be quiet now

- James