JAMMA coin counter wiring

ArcadeGreg

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On a JAMMA harness slots 8 and J are reserved for coin counter 1 and 2 respectively. There are two wires coming from each coin counter. Where does the second wire for each counter attach? I assume ground...Fill me in please.
Thank you,
Greg

PS: Also, does the 8 and J slots provide the 12VDC?
 
You should be using a meter that has a built in diode. The Jamma gameboard does not provide power to the meters.

The "+" (cathode side of the meter's internal diode) goes down to the power supply. if your meter is a 12 volt one then that wire will connect to the +12v terminal on the power supply.

The "-" (anode side of the meter's internal diode) goes to the JAMMA edge connector for either coin counter 1 or coin counter 2.
 
A couple of questions:

1) Is the 1N4148 sufficient to clamp a 12V coin counter?

2) I read Mr. Roberts' page. Is this correct?:

Coin Counter JAMMA.png

or is this?:

Coin Counter JAMMA 2.png

3) Some old boards appear to splice from the coin switch to the counter. Here is a section from Pleiades' manual:

Pleiades diagram.png

Is that the "hot" wire going to the coin switches and counter or the ground? :confused: Were they able to do it with "hot" wires in dedicated cabs because they knew exactly what counters they were dealing with?
 
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A 1N4148 is not correct to use with a meter. You need a 1N4004 or higher. These can be bought at Radio Shack or Fry's if need be.

In a JAMMA setup, the coin meter MUST have a diode connected across it's wires. The meter can have an internal diode (easier wiring) or be connected to an external 1N4004 diode. JAMMA applications usually use a 12 volt DC or 6 volt DC meter. Make a note of the operating voltage printed on your particular meter as that will dictate which terminal on the power supply it will connect to.

If your meter does not have a diode, you will need to wire one in. One meter lead and the cathode (banded side) of the diode are both connected together and then that connection goes to either +12v or +5v terminal on your power supply depending on meter operating voltage.

The other meter lead and the anode (non-banded side) of the diode are both connected together and then that connection goes to JAMMA connector terminal 8 (coin counter 1) if you only have one meter. If this is a second meter this connection would go to JAMMA terminal J instead.
 
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A 1N4148 is not correct to use with a meter. You need a 1N4004 or higher. These can be bought at Radio Shack or Fry's if need be.

In a JAMMA setup, the coin meter MUST have a diode connected across it's wires. The meter can have an internal diode (easier wiring) or be connected to an external 1N4004 diode. JAMMA applications usually use a 12 volt DC or 6 volt DC meter. Make a note of the operating voltage printed on your particular meter as that will dictate which terminal on the power supply it will connect to.

If your meter does not have a diode, you will need to wire one in. One meter lead and the cathode (banded side) of the diode are both connected together and then that connection goes to either +12v or +5v terminal on your power supply depending on meter operating voltage.

The other meter lead and the anode (non-banded side) of the diode are both connected together and then that connection goes to JAMMA connector terminal 8 (coin counter 1) if you only have one meter. If this is a second meter this connection would go to JAMMA terminal J instead.

OK. So it's like this?:

CCJ.png
 
Everyone knows that you are the man, Ken Layton, and I always hope that you might answer my questions. I will do it as you've instructed without reservation.

But for the sake of understanding, which I'm not currently able to be doing...

What keeps the current from just flowing through the connection and bypassing the diode altogether?

CCJ with Visualized Current.png
 
The diode is there for spike suppression of the collapsing magnetic field of the coil inside the meter. It prevents the meter driver transistor on the gameboard from being damaged.
 
Just got up from the computer after reading SOME MORE on diodes and clamping circuits and while brushing my teeth I had some connections form in my head. Maybe. Resistance and the lack of a ground path keep the current in check (doh) and this whole thing is about time interval, no? It's for protection during the working (not resting, as I had supposed) state and all it's really doing is limiting the time that the current has to flow through the meter (and potentially on to the board).

Or am I more retarded than ever?

EDIT: While I was typing this you were answering. Haha! I appreciate you. Thanks to you I am less retarded now. Thank you, Ken Layton.
 
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I'm studying this thread, having a smiliar kind of problem.
The coin meter in my original Donkey Kong cabinet is currently not connected. The cabinet has been converted to JAMMA and a modern PSU put in.
The coin meter uses 24V, which the PSU obviously can't provide, so my idea is to put in a second PSU which puts out 24v only.
As I would only use the meter with the original DK board, presumably I won't need the diode.
My idea is to connect the +24V to Pin 20 on the edge connector ("24v"), and also one of the coin meter wires to that pin, the negative of the power cable to a GND on the edge connector, and finally the second wire of the coin meter to pin X on the pcb ("coin meter").
Do you think this would work? I'm a bit scared wiring 24v to the pcb, but apparently that's what's supposed to happen...
 
24v coin meter? What's that from... a commercial dryer? Don't you just have a 12v meter laying around? I've got a ton on them just waiting to be thrown away.
 
See if the meter will work off of +12v. Connect one line up to +12v, the other up to ground. It may work regardless, and save you from having to get an additional supply *just* for the coin meter.



I'm studying this thread, having a smiliar kind of problem.
The coin meter in my original Donkey Kong cabinet is currently not connected. The cabinet has been converted to JAMMA and a modern PSU put in.
The coin meter uses 24V, which the PSU obviously can't provide, so my idea is to put in a second PSU which puts out 24v only.
As I would only use the meter with the original DK board, presumably I won't need the diode.
My idea is to connect the +24V to Pin 20 on the edge connector ("24v"), and also one of the coin meter wires to that pin, the negative of the power cable to a GND on the edge connector, and finally the second wire of the coin meter to pin X on the pcb ("coin meter").
Do you think this would work? I'm a bit scared wiring 24v to the pcb, but apparently that's what's supposed to happen...
 
Apparently the Donkey Kong of that time require that much steam...
I'll try the 12v to see if that kicks it to life.
The meter is the original one, and it would make me happy if I can keep it. It didn't nearly clock in enough games in its days, just over 6000. This will have to change!
 
So it doesn't work with 12V.
Good news is that it does work with 24V. It's probably been quite a while since last it had some power!
So should I jump in and wire it up as outlined above?
 
So it doesn't work with 12V.
Good news is that it does work with 24V. It's probably been quite a while since last it had some power!
So should I jump in and wire it up as outlined above?
Well, damn, sorry. Was worth a try!


I don;t see why it wouldn't work, but - on that side I can't say for sure, so I yield.
 
I put it all together, but sadly it doesn't work, and I can't figure out why.

Here's what I did:
Put in a 24V power brick
+24 goes to Pin 20 ("+24 for counter")
The negative I connected to Pin 21 (GND)

Also to Pin 20 (+24V) I connected one of the wires of the coin meter.
The second wire of the coin meter I connected to Pin X ("Coin meter")

I checked the continuity, all fine.

Any idea why it doesn't work? I have a High Score Save Kit plugged into the PCB, but I don't think that could be the issue?
 
Yes, I know, so I connected the +24V directly to the respective pin on the edge connector.
 
Trying to wire it up that way may cause you more issues in the future. Like "I'm surprised that your jamma board isn't fried" kind of issues.

Best way would be to use a 12Volt/24V relay (like what laser printers use, so you could scrounge one up from a junked laser printer), or swap out the counter with a 12Volt one.

'Course, we could give better advice if we could see what you're looking at. Post some pics of the setup.
 
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