What am I missing on this Moonwalker?

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I just received a Moonwalker board that I planned on putting in my NEO GEO cab depending on what I felt like playing or displaying. Hooked it up to the jamma connector and it fired right up. The only issue is that I can't start a game. It won't coin up. I have set the dips to 1 coin and I have set it to freeplay, neither will do anything with any of the buttons. From looking at the manual, it looks like a standard jamma setup unless I want the third player which you have to add on a connector for, which I don't need to do. The coin switches and P1and 2 start work fine with the NEO GEO board. Any ideas as to what I'm missing?
 
http://www.basementarcade.com/arcade/library/manuals/m/Moonwalker.pdf

Incase you didn't already have the operator's manual. I'm not having much in the way of luck finding schematics.

First thing's first - I'd go through the usual steps. Check your Power Supply voltages to ensure proper levels during operation, then go through the Pull-Clean-Reinsert game with your socketed IC's, cleaning up cold or suspect solder joints along the way.

There should be a ~5v power signal on your individual control lines (Start/Etc). You could be looking at a dead flipflop that's used by the board to interface with the outside world.
 
I think I may swap out the power supply. It tests ok but I'm having trouble with the NEO GEO board too and it makes me wonder. What is the flipflop?
 
What is the flipflop?

A flip flop is a type of logic gate. Actually, usually the inputs go through a buffer or an inverter of some kind, rather than a flip flop. But, if you follow the coin switch and start button inputs back to the first chip they touch, chances are, it's some kind of logic buffer/gate. If it got "zapped" at some point, it might be dead.

Also, you do realize that Neo Geo and Jamma aren't the same pinout, right? Or, is this a one slot (which is Jamma)

-Ian
 
Augh! Completely forgot about the Buffer IC's.

Good call on RetroHacker's part, too. NeoGeo 2+ slot boards are all custom pinout. You might need a NeoGeo>Jamma adapter.
 
It's a one slot standard jamma. I tried the Moonwalker in another jamma cab and the same thing was happening, no coin up and no freeplay start. How difficult of a fix is it if there is a dead IC? Is there a way to test it?
 
How difficult of a fix is it if there is a dead IC? Is there a way to test it?

Not hard, if that's really what the problem is. First things first, follow the inputs back and see if it goes to a chip. I don't know what Moonwalker looks like, and I don't have a schematic, so I can't tell you what exactly to look at. But follow the inputs back, and find what they go to first. If it's a chip, look up what that chip is, and look at the pinout. You can use a logic probe to see what the inputs and outputs look like when you press the coin/start switches, see if the input is appearing at the chip, and see if it's coming out of the chip.

It's also possible that your problem is something else. There could be a broken resistor network on the inputs, there could be some cut traces on the board, any number of things.

It's also possible that however the control panel is getting it's ground isn't connected properly (gouged trace, something else, etc). With the board installed but the game off, check continuity between the power supply's ground and the control panel ground.

Does the test switch or service switch work?

-Ian
 
Some great things to check. I will be working on it tonight when I get home from work and will report back my findings. Thanks for the input.
 
I sold someone a Moonwalker board once that worked 100% for me but they reported the exact same problem! I sold it to a Brian in Chicagoland back in '96.

Subscribed so I don't miss a thing!
 
I looked at the manual and Moonwalker is not a standard Jamma pinout. Coin 1, for instance, is coming off of one of the spare player two buttons. The problem with this is most Jamma cabs are only wired for coin 1 with the two coin slots daisy chained to the coin 1 circuit.

Try shorting the coin 2 to ground, and if that doesn't work connect the JST connector ground to the Jamma edge connector ground and retry. Also, try changing the dip switch to three players and see what you get...
 
I looked at the manual and Moonwalker is not a standard Jamma pinout. Coin 1, for instance, is coming off of one of the spare player two buttons. The problem with this is most Jamma cabs are only wired for coin 1 with the two coin slots daisy chained to the coin 1 circuit.

Try shorting the coin 2 to ground, and if that doesn't work connect the JST connector ground to the Jamma edge connector ground and retry. Also, try changing the dip switch to three players and see what you get...

I noticed that this morning too. The coin 1 is way low while I remember shorting some pins in the middle to try to get it to coin up based on the standard jamma label. I'll definitely be looking at this tonight. My only question is why didn't the freeplay setting work then? The start buttons are the same pinout.
 
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Two steps forward, two potatoes derp. I'm so confused. Here's what I have done and the results.
1) set it for 3 player and tried to coin or start. Nothing.
2) set it to free play and 3 player and tried coin and start. Nothing.
3) set it to freeplay. Nothing.
4) try shorting coins and starts per the manual pinout not the standard Janna label. Player 3 starts! Can't start anyone else regardless of what coins and starts I short. In fact, almost everything I short causes player 3 to do an attack. WTF!
5) changed back to 2 player setting but nothing will start a game.
6) checked out the board closely and saw no broken or burned traces.
Ideas?
 
Also tried following the traces to any chips but those things are small and duck under paint and other components. If I need to do it I will, but last night I was too frustrated.
 
I think I had that problem. I just don't rememeber how I got around it. I think I swapped the top board(and suicide) with a clutch hitter. But I think both worked with the others bottom board. I either left it at that or I switched it back and then it worked.

If you don't have another sega board handy, try to reseat the top board and the suicide module.
 
Two steps forward, two potatoes derp. I'm so confused. Here's what I have done and the results.
1) set it for 3 player and tried to coin or start. Nothing.
2) set it to free play and 3 player and tried coin and start. Nothing.
3) set it to freeplay. Nothing.
4) try shorting coins and starts per the manual pinout not the standard Janna label. Player 3 starts! Can't start anyone else regardless of what coins and starts I short. In fact, almost everything I short causes player 3 to do an attack. WTF!
5) changed back to 2 player setting but nothing will start a game.
6) checked out the board closely and saw no broken or burned traces.
Ideas?


Are you certain that your cab is wired correctly?

Check the board grounds. You should have continuity across all eight edge connector ground pins on the board. Next check the harness, these grounds may or may not have continuity. If you are missing continuity on both then you need to find a way to link them and see if that resolves your problem. I know for a fact that the grounding circuits in my Big Blue Capcom cab are only connected through the circuit board. If that is how your cab is wired, but your board is layed out expecting them to be linked within the cab, then your grounds are floating and need to be fixed. In my opinion the method my Big Blue is wired up is dangerous to the board, since it forces erroneous voltages across the edge connector.



Here is what I would do next. With the machine powered on/board installed I would check each coin line for power. You should see a signal close to +5vdc. If it is present leave your meter attached and then push the associated button. The line should drop to under 3v, possibly as low as 0vdc. If this operates properly then the problem is most likely in the flip flops mentioned above.
 
It all seems wired correctly although I could be wrong. I checked the coin voltages and got readings of 1.5 on one of them and around 4 on the other. They both drop to below .5 when the switch is clicked and then go back to the original reading. I tried shorting the coins directly at the board as well and got no response from the game except when it's in free play and 3 player mode when the third player starts but no other player will start. Weird.
 
Everything on those old boards is TTL logic, so you should be seeing +5v on your various signal lines. If you aren't, you're looking at a voltage issue. 1.5v is definitely way too low, whereas 4.8+ would be borderline acceptable.

Chances are you're looking at a dead buffer IC or flipflop, depending on how the board handles it's external interfacing. Without a logic probe, you're pretty much stuck.
 
I put another jamma board in the machine and the voltages on the coin switches check out fine which tells me it's the Moonwalker board that is the problem. Anyone looking at this thread do board repairs? Or can you point me to someone? Seems like an easy fix for those that know how.
 
I know this is a necro bump but I wanted to add that Player 1 coin for Moonwalker is the Neo D button aka pin 25 on the jamma harness.
 
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