Dead controller ports on MV-1F

Gummy Bear

Gummy Bear

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Howdy y'all.

I have an MV-1F which was fine and dandy, now it cannot be controlled.
It boots fine (UniBIOS doesn't chime up with any errors) demo's the game fine, sounds fine, looks fine, but just can't be controlled.

I've tried controlling it through the edge connector and plugging pads and sticks (of the AES variety) into it, but no joy.

Nothing at all....


Any ideas, fellas?
 
Last edited:
MKL

MKL

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Take the multimeter and read the voltage on each Jamma input pin. You're supposed to always read 5v. Basically the circuit is as follows:

Code: 
           1K                 220
5v------/\/\/\/------|------/\/\/\/------I/O controller IC
                     |
                     |
                     |
                      / Pushbutton
                     /
                     |
                     |
                     |
                     |
                   GROUND
 
Razoola

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You may also want to check test mode if you can get there and see if the problem is with all buttons or just start and coin etc.

Raz
 
Neo Alec

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Make sure the Unibios isn't set to arcade protect with the free play switch off on the board.
 
Gummy Bear

Gummy Bear

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Correction.

I AM getting power to all the points on the edge connector (+5v)
But the controller ports on the side of the board are completely dead.

As these are what I use, you can see how this is annoying.


What should I be looking for?

A broken trace?

Something that's blown?



Any help would be great, guys.
 
Gummy Bear

Gummy Bear

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Neo Alec said:
Make sure the Unibios isn't set to arcade protect with the free play switch off on the board.
Click to expand...


Hi Alec.

The backup RAM battery is disconnected at the moment, so the system wouldn't be in arcade protect mode.
 
MKL

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If the jamma pins work and the ports don't then it can only be broken traces. But all of them??
 
Gummy Bear

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MKL said:
If the jamma pins work and the ports don't then it can only be broken traces. But all of them??
Click to expand...

That's what I thought, mate. :glee:
Doesn't sound very likely does it?

There must be something common for both ports that's broken.....
A GND of some sort, perhaps?
 
MKL

MKL

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Well you should be able to easily check if the ports are grounded on pin 1. However it doesn't sound very likely that the ground connection is broken because it's not a trace like the others, the ground pin is soldered directly to the ground plane in between the PCB.

What you could do is start checking from the ferrite cores just behind the ports: from there the traces will fork and go to the ports and to the jamma connector:

Code: 
                        /---------jamma connector
-------|ferrite|-------/
                        \
                         \--------joy port

If the connection to the joy port were broken you'd have:

Code: 
                        /---------jamma connector
-------|ferrite|-------/
                        \
                         \---  ---joy port

But as I said it doesn't seem very likely that this occurred to each and every trace, unless the board was scratched real bad on the bottom.

Then again it could also be a problem with the joystick cord plug that doesn't make good contact when plugged into the ports (but both?). Clean the port pins. BTW Have you tested the joysticks on another setup to see if they work fine?
 
Razoola

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There is actually something special about the joystick ports on the neogeo. There are 3 pins from the 15 that are outputs. Its possible that if one of these is broken it could make the entire joystick port not work correctly but I'm not 100% sure of this.

Raz
 
mainman

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I was thinking if the the controller inputs where somehow multiplexed on the PCB ( not the controller of course ) to reduce the bus line which would explain why you have no response from any of the joystick functions, because if the chip that control the input function is damaged that would cause all the input function to not respond. Did you try putting the original bios back in yet?
 
Gummy Bear

Gummy Bear

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MKL said:
Well you should be able to easily check if the ports are grounded on pin 1. However it doesn't sound very likely that the ground connection is broken because it's not a trace like the others, the ground pin is soldered directly to the ground plane in between the PCB.

What you could do is start checking from the ferrite cores just behind the ports: from there the traces will fork and go to the ports and to the jamma connector:

Code: 
                        /---------jamma connector
-------|ferrite|-------/
                        \
                         \--------joy port

If the connection to the joy port were broken you'd have:

Code: 
                        /---------jamma connector
-------|ferrite|-------/
                        \
                         \---  ---joy port

But as I said it doesn't seem very likely that this occurred to each and every trace, unless the board was scratched real bad on the bottom.

Then again it could also be a problem with the joystick cord plug that doesn't make good contact when plugged into the ports (but both?). Clean the port pins. BTW Have you tested the joysticks on another setup to see if they work fine?
Click to expand...


Hi MKL.

I have tested my three controllers (2 pads and a new style stick) on a friend's AES. All fine and dandy, yet none of them work on my board.

Whatever is wrong, it's wrong with the MVS, not the controllers.

The board doesn't appear to be scratched. I'll check the traces tomorrow with a mulitmeter.


Thanks for your continuing help, mate.

It's much appreciated. :)
 
Gummy Bear

Gummy Bear

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Razoola said:
There is actually something special about the joystick ports on the neogeo. There are 3 pins from the 15 that are outputs. Its possible that if one of these is broken it could make the entire joystick port not work correctly but I'm not 100% sure of this.

Raz
Click to expand...


Howdy partner. :tickled:

Good knowledge.

I'm going to check the traces tomorrow.
If any are broken, I'll let you know.
 
Gummy Bear

Gummy Bear

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mainman said:
I was thinking if the the controller inputs where somehow multiplexed on the PCB ( not the controller of course ) to reduce the bus line which would explain why you have no response from any of the joystick functions, because if the chip that control the input function is damaged that would cause all the input function to not respond. Did you try putting the original bios back in yet?
Click to expand...


Hi Mainman.

Again, good knowledge. :glee:
It does sound feasible (though I hope you're wrong).
Broken chips........

I'll do as you suggest and stick the original BIOS in it tomorrow (if I can remember where I put it).
 
MKL

MKL

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I would make sure the jamma input pins actually work. I don't know if this is a consolized unit but even if you don't have a cab or a supergun you could take a piece of wire and short the coin (and then start, etc.) pin and see if it works. Because if the chip that controls the inputs were damaged the jamma pins wouldn't work either.
 
Gummy Bear

Gummy Bear

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MKL said:
I would make sure the jamma input pins actually work. I don't know if this is a consolized unit but even if you don't have a cab or a supergun you could take a piece of wire and short the coin (and then start, etc.) pin and see if it works. Because if the chip that controls the inputs were damaged the jamma pins wouldn't work either.
Click to expand...


Good thinking, Batman!!

I'll do that first thing in the morning.
It is a consolized unit that I did a few months ago.
 
Gummy Bear

Gummy Bear

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Tried the original BIOS. No joy.
No traces look broken.

I'm going to strip it down, clean it proper and get the multimeter on the job in a bit.
 
Gummy Bear

Gummy Bear

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Joy!!

I took it to bits and gave it a right good cleaning with my trusty camera brush and an air duster.
Everything now works fine. There must have been a little bit of wire or something shorting something out.

All is now right with the world. :glee:


Thanks for all your time, guys.

Much appreciated.
 
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