AES voltage regulator?

[izarate]

I recently found a NeoGeo AES. The unit works fine, but I have a little problem with it. Well, not a problem, but a situation:

Using a cable modem power supply 9V 3A tip negative: doesn't work
Using a multivoltage regulated AC adapter at 9V 1.8A tip negative: doesn't work, because of the <2A amperage, I assume.
Using a multivoltage regulated AC adapter at 7.5V 2.5A tip negative: the screen goes up for a second
Using a multivoltage regulated AC adapter at 6V 2.5A tip negative: works
Using a multivoltage regulated AC adapter at 5V 2.5A tip negative: works

After that I thought that maybe the internal voltage regulator was somehow broken but the thing is, I couldn't find it. Where is it located? It's a NEO-AES board if that helps.

What I would like to do is to be able to use the cable modem power supply.

[ooXxXoo]

Is it a Japanese or an American NEO-AES?....What is the serial #?....

[izarate]

The AES is American, but the board is made in Japan if that makes a difference. The serial is 90A011968

[ooXxXoo]

If you aren't for sure to whats the problem with your system, I'll suggest to run your NEOGEO buit-in diagnostic color screen test....
Just boot the system without a cartridge a take a note of the color on the screen:

BLUE: All test passed

RED: work Ram error

GREEN: palette Ram error

YELLOW: video Ram error

PINK: Bios selfcheck error

CYAN: memory card error

And if your problem is definitely power related, I'm not for sure at the moment but I remember seeing a power regulator at the front, near the Reset button (5 pin leg IC power regulator)

[FABombjoy]

Some are internally regulated, some are external. The serial number is irrelevant - the code on the main PCB is the only reliable way to determine what power supply. NEO-AES boards are externally regulated. Original supply is 5V 3A.

Hopefully you didn't shorten the life of the board by plugging in all of those incorrect power supplies.

[izarate]

Some are internally regulated, some are external. The serial number is irrelevant - the code on the main PCB is the only reliable way to determine what power supply. NEO-AES boards are externally regulated. Original supply is 5V 3A.

Hopefully you didn't shorten the life of the board by plugging in all of those incorrect power supplies.

ugh...I didn't want to have to use my multivoltage adaptor for it. I'll try to put a regulator + heatsink in the cable modem power supply. Since plenty of sites listed the AES as 10V 3A I thought that it had to have an internal regulator.

Thanks for the information. I was going crazy trying to find the regulator IC. I just tested the unit for a few seconds so I don't think I've caused any damage.

[izarate]

Well, I just installed the regulator:

http://img511.imageshack.us/img511/3337/img5414sv0.jpg

I couldn't open the power supply and decided to install it on the outside. I had already cut the cable before because I had to reverse the polarity of the power supply, so I put the regulator there. I just played Mutation Nation for half an our and the clip-on heatsink seems to be holding up fine, but for the peace of mind I'll try to look for something bigger.

Now, another question: sometimes, when I hit reset or I turn the unit off and on, the NeoGeo sound starts but then stops and all you hear is a single tone, even when the game starts. Is that a sign of the audio capacitors failing or something else? Right now it seems to be random.


Oh, the power on self test shows up fine (blue screen).

[FABombjoy]

Now, another question: sometimes, when I hit reset or I turn the unit off and on, the NeoGeo sound starts but then stops and all you hear is a single tone, even when the game starts. Is that a sign of the audio capacitors failing or something else? Right now it seems to be random.
Assuming it isn't due to dirty cartridge contacts, it's probably related to the Z80 or the 2610.

From my standpoint, if someone brought me that board and said that they had put 9V through it, I'd declare it a writeoff. It's amazing that it even still boots up ;)

[jb143]

Part of me doesn't like seeing the regulator without a cap in the circuit but if it's working then it's probally ok. If it's not getting hot then the heat sink is probally ok too. If you havn't done it yet though, you might want to add a bit of heat sink grease to help transfer heat.

[channelmaniac]

What regulator chip did you use? A 7805 or LM317 will NOT have enough current capacity to run the game. They are rated at 1 to 1.5A in the TO-220 package (depending on manufacturer and suffix)

You should buy a simple 5v 3A laptop power adapter or find an adapter for a PC peripheral that you can modify with the correct size plug to fit the AES.

I'm wondering if you didn't damage the unit with the wrong supply.

[izarate]

Part of me doesn't like seeing the regulator without a cap in the circuit but if it's working then it's probally ok. If it's not getting hot then the heat sink is probally ok too. If you havn't done it yet though, you might want to add a bit of heat sink grease to help transfer heat.

I'm going to add the capacitor but yesterday I just wanted to test it.



What regulator chip did you use? A 7805 or LM317 will NOT have enough current capacity to run the game. They are rated at 1 to 1.5A in the TO-220 package (depending on manufacturer and suffix)

You should buy a simple 5v 3A laptop power adapter or find an adapter for a PC peripheral that you can modify with the correct size plug to fit the AES.

I'm wondering if you didn't damage the unit with the wrong supply.

It's a 7805. I didn't know about the current cap but yesterday I didn't had any problem, except for the audio issue I mentioned. After posting I went and played for another hour and a half. The sound issue didn't present itself again but as I said, it seems to be random, so I can't be 100% sure. So far it seems to be doing great and the self test shows up as OK (blue screen).

I settled with that power supply because it was the only one I could find with more than 1.5A. I had my multivoltage adapter but I use it for testing purposes only, so I wanted to get one exclusively for it.

Anyway, what regulator do you recommend?

[channelmaniac]

LM323

http://www.st.com/stonline/products/literature/ds/2165.pdf

RJ

[izarate]

I couldn't find any LM323 so I came up with this:

http://img297.imageshack.us/img297/4792/5v3awu7.gif

Would this suffice?

[FABombjoy]

I believe that Base-Emitter voltage drop will lower output to about 4.4V. You would also need a current limiting resistor on the collector. You could locate a 5.6v zener & construct a series-pass regulator out of that...

Or, do something like this (http://www.elecfree.com/electronic/5v-3a-regulate-power-supply-by-tip2955/)...

Or salvage a 5V regulator from an AT / ATX power supply. Or just use an AT power supply.

[channelmaniac]

I couldn't find any LM323 so I came up with this:

http://img297.imageshack.us/img297/4792/5v3awu7.gif

Would this suffice?

NONONONONONONO!!!!!

Two problems:

1. You need to put a potentiometer inline with the ground leg of the 7805 to boost the voltage slightly because of the forward voltage drop of the transistor.

2. And this is a biggie. If that transistor shorts out there is NOTHING to stop the full amount of unregulated DC power from going straight into the AES.