Isolating power supply in Jamma cab

[LeedsFan]

I'm getting to the point where I need to look at the wiring in my Jamma cabinet. The cabinet is fully working and I'll be using a J-Pac and ArcadeVGA card to connect up my PC.

However, I hear that it's very important to isolate the power supply of the cabinet somehow, as the machine will have no game board in there to take a load. But I still need to have the arcade monitor connected to the mains, together with the marquee light if possible.

So how exactly do I do this?  The cabinet concerned is a generic one made by a company in the UK called Electrcoin.
The power supply sits at the back and bottom of the cab and has about six plastic plugs of various sizes going into it.  Sorry for the vague description, but I have no digital camera at the moment.

With Jamma being an industry standard, then won't the wires in the loom be the same colour as all other Jamma cabs?  If someone can point me in the right direction it would be much appreciated.  

[RayB]

JAMMA was a standard for the pin-out (the edge connector) specifiying which pin would be for what (ie: one for joy up, one for fire button 1, one for +5 volts, etc, etc).

That's as far as it goes. No color standards.

Your best bet is to just see which power cords go to what. It should then be obvious to you which you need to keep and which can go.

[LeedsFan]

So is it just a case of unplugging the stuff that is unnecessary? Do I simply identify the connection blocks for monitor and marquee and unplug the rest?

I'm not too sure about this..... the power supply will still be outputting power for the game board even though it's not connected. Is this right?

Or would I be better off disconnecting the power supply altogether and wiring up the monitor and marquee totally seperately? (And yes.... I would check that the ground is not through the power supply first.  )

And how do the buttons get their power? From the J-Pac or from the cabinet power supply? The first three buttons always got their power from the original power supply. Does the J-Pac reverse the way the power is supplied? I'm thinking that power used to go through the connector and into the old game board..... but now it will come throught the PC and into the J-Pac, therefore through the connector the other way, and then into the loom to the buttons.

[DYNAGOD]

the monitor and marquee are "not" connected to the switchable power supply..the monitor/marq is connected directly to the AC mains.

 

[SirPeale]

The monitor is more than likely connected to an isolation transformer, which is connected to mains power.  You should find the arcade power supply and remove it.  Likely there is mains power going to it, so you'll have to do something with those wires so they don't short.

It's really not complicated at all, once you have a look at it.  You'll look at it, and say "Oh, jeeze, I was worried over nothing."

[LeedsFan]

The monitor is more than likely connected to an isolation transformer, which is connected to mains power.  You should find the arcade power supply and remove it.  Likely there is mains power going to it, so you'll have to do something with those wires so they don't short.

It's really not complicated at all, once you have a look at it.  You'll look at it, and say "Oh, jeeze, I was worried over nothing."

I think you may be right.    I did a bit more research on the net through Google and came across this thread on jammaplus.com...

http://www.jammaplus.com/forum/forum_posts.asp?TID=719&PN=1

This is basically the exact same question I've asked here. Can anyone confirm that the response in this thread is correct? (Please ignore their childish spat  )  I've looked at my power supply and there is a seperate box with +5V, -5V etc.etc. as described.

Also, there is a seperate switch on top of my cabinet. Does this switch the entire machine on/off without unplugging the mains? Or is it just for the marquee light?  (Sorry, I have no power where my machine is currently located so I cannot try anything out)

[SirPeale]

What they said there is pretty much what I said here.

[RayB]

The switch on top would be the primary power switch that turns power on for EVERYTHING. Don't touch it.

Further down the line (power lines) from that switch, the AC power will go into a few parts. There should be a large heavy metal cube. That's the Isolation Transformer. The monitor should be taking its power from that Iso Trans.

The OTHER box, with +5, +12 etc is the Switching Power Supply. It powers the board and maybe the coin door lights and coin counter if there is one. It will NOT be connected to the monitor.

Other parts you might find in there are fuses and a small silver box. That small silver box is an AC RF filter. It's supposed to filter out radio frequency interference. You should probable leave that in.

So in the end, if MAMEing the cab, you need to remove the Switching Power Supply, and you won't need the 3 fuses that are likely attached to it. Everything else you can keep as is.

~Ray B.

[LeedsFan]

Many thanks for all your input guys. I think I've got this sussed now, and like Peale said it was pretty easy. I didn't even remove the switching power supply unit (must I physically remove it?).  I just unplugged the block connector with the power leads that went to it and taped it up. Nothing else to do.

I found the AC RF filter (it was a round cylinder on my cab) but I left it as is. Same with the fuses. If there's no power to them (or the switching power supply) I don't see any need to remove them.

[SirPeale]

Yeah, that's fine.  As long as it's not powered.

You can leave that RF filter, though.  Should be the first place the mains power goes.

[RayB]

No, you don't have to physically remove the PS. In fact, it might help re-sale value to leave it in, especially if you stick to the JAMMA standard.