NeoGeo power supply issue?

super56k

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Hello fellow KLOVers. I just picked up a dead but complete Neo-Geo and am attempting to bring it back to life. When you turn it on, the power supply does nothing. There is no power being output and the fan does not spin.

The previous owner bought a new power supply from HAPP and it too did nothing. When I got it, it came with both power supplies. Upon closer inspection, I found the power switch in the cabinet was wired BACKWARDS. I mean to say the wires where crossed. I wired it the correct way and tested for proper continuity with a multimeter. I now know that the switch is working and the wiring going to it is fine. It still won't come on.

EDIT: Here is a picture for clarity:
NGPS.jpg

Insted of brown and black being connected and blue and white being connected, brown and white where connected and blue and black where connected.


I took the power supply out of the cab and bridged the two separate connections for the power switch on the power supplies harness with bits of wire and it still won't come on. I tried resetting it's 5amp breaker and I even opened it up looking for any obvious signs of death. No burn marks or popped caps and the one fuse inside is still good.

Is it possible that having the power switch wired in this fashion killed the new power supply? Should the power supply be able to power up without a load as long as those switch connections are bridged?
 
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Unlikely any damage has been done if the fuse is intact. It's quite possible it won't turn on without a load, to avoid risking damage to your game try wiring up an old hard drive or something to test it with.
 
Unlikely any damage has been done if the fuse is intact. It's quite possible it won't turn on without a load, to avoid risking damage to your game try wiring up an old hard drive or something to test it with.

That's a great idea. Now if I can just figure out what wire goes where. This is the strangest power supply I have ever messed with. It's not like those peter chou switchers or like an ATX.
 
That's a great idea. Now if I can just figure out what wire goes where. This is the strangest power supply I have ever messed with. It's not like those peter chou switchers or like an ATX.

Looks like a modified AT to me (precursor to ATX, was the de-facto PC standard back in the DOS days). They all had a four-pin manual power switch like that.

If the switch wires were wired wrong, it likely blew a fuse INSIDE the power supply. I'd crack it open.
 
Looks like a modified AT to me (precursor to ATX, was the de-facto PC standard back in the DOS days). They all had a four-pin manual power switch like that.

If the switch wires were wired wrong, it likely blew a fuse INSIDE the power supply. I'd crack it open.

"and I even opened it up looking for any obvious signs of death. No burn marks or popped caps and the one fuse inside is still good."
 
"and I even opened it up looking for any obvious signs of death. No burn marks or popped caps and the one fuse inside is still good."

Ach, I missed that somehow.

Do you have some pictures of the whole power supply? I remember seeing that sticker but can't place it.
 
I'll have to wait til I get a chance to look at the power supply tonight but in the picture the DC connector looks like a 9pin but the sticker calls it a 12 pin. Which one is -12v?
 
I'll have to wait til I get a chance to look at the power supply tonight but in the picture the DC connector looks like a 9pin but the sticker calls it a 12 pin. Which one is -12v?

But it only lists 8 pins... hmm. I'd wager you probably don't have -12. Yellow 12, Red 5, black GND, white -5... no wires left. I don't think Neo Geo uses a -12 anyway.

Is it totally dead? That switch should be pretty early in the circuit, so tracing the input power may be promising.
 
But it only lists 8 pins... hmm. I'd wager you probably don't have -12. Yellow 12, Red 5, black GND, white -5... no wires left. I don't think Neo Geo uses a -12 anyway.

Is it totally dead? That switch should be pretty early in the circuit, so tracing the input power may be promising.

Yes, the fan does not even spin and I don't know how to reset the 5AMP breaker on the PSU.
 
I found another problem...

2012-03-27_23-12-45_221.jpg


This connector / cable on the memory card board has a burn right through it. I unplugged both connectors from this board on the main PCB side of things. I tried disconnecting the cable from the memory card board but it is actually MELTED in place. With both of these cables disconnected from the main board, the PSU still will not fire up.
 
Look at the memory card slot. Two to 1 says the pins are all bent up.

As for the power supply, they are not hard to troubleshoot if you want to try to repair them. I have troubleshooting instructions on my repair logs pages.

Have you checked the resistance on the various voltage outputs from the PS to see if you have a short somewhere else? Switching power supplies will shut down if there is an overcurrent or overvoltage condition.

RJ
 
Look at the memory card slot. Two to 1 says the pins are all bent up.

As for the power supply, they are not hard to troubleshoot if you want to try to repair them. I have troubleshooting instructions on my repair logs pages.

Have you checked the resistance on the various voltage outputs from the PS to see if you have a short somewhere else? Switching power supplies will shut down if there is an overcurrent or overvoltage condition.

RJ

The whole memory card slot is all screwed up. It looks like someone shoved something in it.

I have two PSUs, one is the one the original and one is a brand new replacement that the last owner tried to install. Neither do anything. The fans don't spin. Nothing powers on (not even the monitor that hooks up to it.) All the wiring I have tested thus far looks fine. The new PSU has a 5amp breaker on it insted of a fuse and it looks like is up to me. Does that mean it's tripped? How do I reset it? It won't stay down when I press it.
 
The way you describe how the wiring was hooked up likely wouldn't hurt anything, you just crisscrossed the wires into the switch... which still would have turned it on. Anything's possible though.

I'm almost positive on those power supplies you DO need a load on them, though, or they won't turn on. I had the same issue with one I put in a machine, I kept trying to check the power and it was dead, but once hooked to a board turned itself on.

So; you need to hook the power supply into the harness with the game pcb plugged in and turn it on. What sucks about doing that, is if your power supply has been adjusted (like you may have done turning the knob when you didn't get a voltage?????) it may be putting out enough juice to screw up the board. Also if you turn the knob way down, the power supply likely won't turn on either if it's nowhere near the right voltage.

My guess: Your new power supply is fine, it just needs to be plugged in again with the wires going the right way.
 
The new PSU has a 5amp breaker on it insted of a fuse and it looks like is up to me. Does that mean it's tripped? How do I reset it? It won't stay down when I press it.

Bingo! That would be your problem. Look at your old one and see if you can figure out how it trips/resets.
 
The way you describe how the wiring was hooked up likely wouldn't hurt anything, you just crisscrossed the wires into the switch... which still would have turned it on. Anything's possible though.

I'm almost positive on those power supplies you DO need a load on them, though, or they won't turn on. I had the same issue with one I put in a machine, I kept trying to check the power and it was dead, but once hooked to a board turned itself on.

So; you need to hook the power supply into the harness with the game pcb plugged in and turn it on. What sucks about doing that, is if your power supply has been adjusted (like you may have done turning the knob when you didn't get a voltage?????) it may be putting out enough juice to screw up the board. Also if you turn the knob way down, the power supply likely won't turn on either if it's nowhere near the right voltage.

My guess: Your new power supply is fine, it just needs to be plugged in again with the wires going the right way.

This is what I have been trying all along. I have the PSU hooked up to the cab completely. It will not power on with or without being connected...
 
The way you described it it does sound like your 'breaker' is tripped, does it look damaged or anything? Usually you can just press them back in.
 
Oh also have you tried to get ghetto with it and physically hold the breaker in, while you turn the game on? lol

I have tried everything with that little breaker. It won't stay down and I have tried holding it in before powering up, during and after. The PSU does squat. As I mentioned before, I opened the PSU up and the fuse inside was good as well. No obvious signs of damage.
 
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