Neo Geo AES 1st revision flickers all the time

ebichu

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Hey guys,
recently got a Neo Geo 1st revision with flicker problems. I recorded a video.

http://www.youtube.com/watch?v=ANOqKMWStCQ

What I already did:
- Cleaning the cart slot
- Cleaning the cartridge
- tested 2 RGB Cables
- had a look on the DIN Connector's soldering points
- changed the Unibios

Tested on a Samsung LCD TV with XRGB3 and without and on an old Philips Amiga CRT TV. Same problem..

Any suggestions?

Thanks!
 
Last edited:

NeoGeoNinja

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I'm no expert on this sort of stuff at all, but could that be related to the power supply feeding the Neo?

It looks as though it could be power related to me. Just a thought...
 

ebichu

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Hm, not the baddest thought.. But how can I check if it's an power related issue?
 

RockstarRunner

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I've had one issue or another with nearly all my systems regarding sync, which I fixed in all cases by routing composite sync to scart pin 20 and putting a buffer on the line (Source -> 220uF cap -> 75 ohm resistor -> Pin 20)
 

Xian Xi

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If it's a 1st revision you need to swap out the 100uf caps with 470uf ones and use 75ohm resistors.
 

ebichu

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If it's a 1st revision you need to swap out the 100uf caps with 470uf ones and use 75ohm resistors.

It is a 1st revision (with Daughterboard).
Which 100uf caps are we talking about? And wich 75ohm resistors exactly?
Thanks! :)

Edit: Okay, found out which 100uf caps you're talking about.

2 more questions:
- Can you please show me where I have to put the 75ohm resistors in?
- There are alot of 470uF Caps on eBay. Like 16/25/35V... Which are the right ones?

Tranks alot! :)
 
Last edited:

Xian Xi

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They are located right behind the AV socket.

There will be 6 capacitors lined up, the first one on the left you do not change. The other 5 you do. Same goes for the 68ohm resistors, leave the first resistor there and swap out the other 5.

Personally I use 470uf@10v since they are a bit smaller and easier to fit in a row.
 

ebichu

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Ah thanks, just as I thought :)
And thanks for the info about the caps!

I will oder them and of course will reply here, if everything went fine.
 

ebichu

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Sadly no difference after changing everything.
I attached a photo where you can see what resistors and what cons I changed.
The resistors are 75Ohm now, the Cons are 470uF ones.

Any more suggestions? :/

ng.jpg
 

Xian Xi

JammaNationX,
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Only other things to try are putting a 0.1uf cap on the sync line output or you can try putting a potentiometer on the sync line and adjust the signal strength if needed.
 

ebichu

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Can you please show me where exactly I have to put the 0.1uf cap?
And if this is not working, where to connect the potentiometer?

If nothing of this works, there is nothing else I can do? Thought this is a more or less common problem which is solvable :/
 

ebichu

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Awww man, got another 1st revision board with the exact same problem. Was changing the exact cons and resistors and still the same issue. :/
 

Billkwando

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Awww man, got another 1st revision board with the exact same problem. Was changing the exact cons and resistors and still the same issue. :/

This does not bode well for me. I'm glad I didn't try to do that mod yet.

Edit: Actually, flickering and rolling aren't the same thing. I've never seen that flicker issue before, but I've seen plenty of rolling.
 
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Xian Xi

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Did you already test out the power supply like mentioned above? I didn't see any report about it so I am guessing you didn't. If you have another power supply with the same voltage and polarity you can give it a try. What power supply do you have, 5v or other?
 

ebichu

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Didn't test it so far. It's a 5V, yes.
I don't have another one. But it could be the problem since the 2nd NG I got had a broken power supply and I used the one from the 1st NG. Oh.... :D

So I will masure the supply and write down the results here.
 

theboy995

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Didn't test it so far. It's a 5V, yes.
I don't have another one. But it could be the problem since the 2nd NG I got had a broken power supply and I used the one from the 1st NG. Oh.... :D

So I will masure the supply and write down the results here.
did you solve it?
 
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