When is -5v used on a switcher?

sohchx

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I have a switcher in a JAMMA game from 1987 that is not using this, but I hear that the older games do. Is this game not old enough to be using this? Also why do some switchers have OV on them and some have FG? What do these mean? You have to excuse my Noobness as I am having a switcher issue right now and am trying to learn more about them and how they work.
 
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Many games use the -5v for assorted circuits. Some use it to power lights, some use it for creating a 10v sweep (coupling it with the +5v), and I am sure there are other uses. It is a circuit on the Jamma standard because so many Jamma games use it.
 
I have a switcher in a game from 1987 that is not using this, but I hear that the older games do. Is this game not old enough to be using this? Also why do some switchers have OV on them and some have FG? What do these mean? You have to excuse my Noobness as I am having a switcher issue right now and am trying to learn more about them and how they work.

OV = 0V = zero volts = ground. Probably the same as FG which is...

FG is 'field ground' which is usually the center tap on the secondary side of a transformer. What's neat about transformers is, since their outputs (secondary side) are isolated from their inputs (primary side) you can attach any of the outputs to chassis ground and create either positive or negative voltages from the rest of the outputs. You can also connect the outputs from two transformers in such a way as to get a higher or lower voltage than you could from a single transformer. This is known as power supply 'stacking'.
 
OV = 0V = zero volts = ground. Probably the same as FG which is...

FG is 'field ground' which is usually the center tap on the secondary side of a transformer. What's neat about transformers is, since their outputs (secondary side) are isolated from their inputs (primary side) you can attach any of the outputs to chassis ground and create either positive or negative voltages from the rest of the outputs. You can also connect the outputs from two transformers in such a way as to get a higher or lower voltage than you could from a single transformer. This is known as power supply 'stacking'.

So when wiring up a PS how will I know if I need to use one of these two if the game manual does not state it? I assume that if it's not specified in the directions it is not needed?
 
If the manual doesn't call for any "creative" wiring then it is not necessary. Most games use the standard +5vdc, +12vdc, and -5vdc. The ground coming off of these lines should be wired to the ground point on the switcher, not the FG. The voltages listed are in relation to the switcher ground, using a different grounding point could cause a higher or lower difference of potential.
 
If the manual doesn't call for any "creative" wiring then it is not necessary. Most games use the standard +5vdc, +12vdc, and -5vdc. The ground coming off of these lines should be wired to the ground point on the switcher, not the FG. The voltages listed are in relation to the switcher ground, using a different grounding point could cause a higher or lower difference of potential.

hmmmm... Well I have an issue with a game right now and at the switcher every wire slot is occupied accept for the FG and -5vdc spots. Shouldn't -5vdc be used at all times?
 
If it's the Contra you have been working on then NO, it does not need it.
Just +5v and +12v.

Typically when I wire up a new JAMMA harness I always go ahead and wire the -5v in because you never know what game may be in the machine later down the road. Or simply for testing boards purposes.
If a game does not need it, then it won't use it. Meaning those pins will generally be a dead end on the board anyways.

The FG on the power supply from your other thread would be the AC ground.
The 0v is the game pcb ground.
 
The FG on the power supply from your other thread would be the AC ground.
The 0v is the game pcb ground.

For video games, field ground and logic ground (0V) should be tied together to chassis ground at the power supply. Less sophisticated power supplies like the Peter Chou take care of this for you inside the case.

BTW earlier I was talking about power supplies in general. There's almost no case where you would need to stack a power supply for a video game unless you were hacking! :-O
 
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For video games, field ground and logic ground (0V) should be tied together to chassis ground at the power supply. Less sophisticated power supplies like the Peter Chou take care of this for you inside the case.

Agreed....
Just trying to keep the basics simple for the fella.
Ya know, "Which wire goes here?" type of thing.
 
Agreed....
Just trying to keep the basics simple for the fella.
Ya know, "Which wire goes here?" type of thing.

That's exactly what I need. Why can't I find any installation instructions for switchers anywhere? Do brand new ones even come with them? I know the chinese ones don't. It seems everything that I buy brand new that's arcade related never comes with instructions and I need them. I know cars, not games. I checked into getting a tech to come fix it and he wants $150 just to come to the door, then $50 per hr. That's more than I paid for the cab!!! I even had SupeBee, a fellow Klov'r come by and look at it and he's stumped to. He's been in the game way longer than me. I really, really do not wanna give up on this cab especially since I've wanted it since I was 9 yrs old.
 
Get some more pics of your setup and we can jump back over to your other thread to keep it all together.
Knowing what game was "originally" in that cabinet may help as well, them round fuse holders is throwing me off.
 
Agreed....
Just trying to keep the basics simple for the fella.
Ya know, "Which wire goes here?" type of thing.

You're right. Looking back I guess I wasn't much help this time around sorry. :p

Take a look here. I didn't read the text, but at the very bottom there's a good diagram showing the AC hookup. The DC hookup should be simple - just wire the correct voltages from your main board harness to the switching power supply, i.e. +5V to +5V, +12V to +12V, GND to GND, etc.

http://arcadecontrols.com/BBBB/acwiring.html
 
That's exactly what I need. Why can't I find any installation instructions for switchers anywhere? Do brand new ones even come with them? I know the chinese ones don't. It seems everything that I buy brand new that's arcade related never comes with instructions and I need them. I know cars, not games. I checked into getting a tech to come fix it and he wants $150 just to come to the door, then $50 per hr. That's more than I paid for the cab!!! I even had SupeBee, a fellow Klov'r come by and look at it and he's stumped to. He's been in the game way longer than me. I really, really do not wanna give up on this cab especially since I've wanted it since I was 9 yrs old.


What you are asking for is really simple. You need to wire two AC wires to the switcher. You should use two wires that are live when the cab is powered on and dead when it is powered off. In the Contra manual you posted these wires are red/white and black/white as shown on .pdf page 3. Then you need to connect the +5, +12, and ground to the rest of your harness. You may need to trace the lines from the pcb connector as shown on the bottom of .pdf page 5.

That is all there is to installing a switcher.
 
Get some more pics of your setup and we can jump back over to your other thread to keep it all together.
Knowing what game was "originally" in that cabinet may help as well, them round fuse holders is throwing me off.

We were trying to figure out if it was dedicated. It has Konami badging on the outside of it but that stuff may just come with the kit.
 
What you are asking for is really simple. You need to wire two AC wires to the switcher. You should use two wires that are live when the cab is powered on and dead when it is powered off. In the Contra manual you posted these wires are red/white and black/white as shown on .pdf page 3. Then you need to connect the +5, +12, and ground to the rest of your harness. You may need to trace the lines from the pcb connector as shown on the bottom of .pdf page 5.

That is all there is to installing a switcher.

The correct AC wires are already on the switcher as is everything else. I posted pics of everything connected to switcher in this thread.

http://forums.arcade-museum.com/showthread.php?t=125615
 
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