The newer Revision 5 or 6 of Neo Geo have bad RGB-Output Signals. It looks like a grid layed over the picture.
We can take care of the RGB-Fix if you are not able to do it by yourself
left site: verticallines, right site: OK!
To remove the vertical lines you can do the RGB bypass I found here.
First you have a look into your neogeo to see if you have one of the „bad“ Revisions.
use a flashlight to see the revision of your neogeo board
use a flashlight to see the number
Here you can see the Layout Revision
Part #1
Removing Capacitors, Resistors and replaceing with 3 75Ohm Resistors
Remove the 4 capacitors and 3 resistors
You have to remove the four marked capacitors (red,green,blue,yellow) and the 3 Resistors (red,green,blue).
After this it looks like this
removed capacitors and resistors
Now you have to reconnect the rgb Signal via 75 Ohm Resistors.
I am using some shrinking tube look here.
The Sync Signal (yellow) doesn’t need 75 Ohm you can wire it directly
3 resistors and sync wire
Part#2
directly at the other side of the mainboard you find the crystal (the cause of the problem)
you have to cut of the rgb-signal in this area, so the crystal can’t sending bad signals into the rgb-wires.
cuting rgb signal
You have to cut both sites to be sure.
cutting done
cutting done
After further reading the links above, it seems to be allright if you only do Part#2.
When I will do the next neogeo I will check it and give this site an update, because I done first Part #1 and the picture was quite better. After doing Part#2 I didn’t saw any better picture.
Part #3 50/60 Hz
If you have a Pal Revision all games running at 50Hz you have to cut of the connector between the pal jumper.
The following picture is showing a NTSC Console.
Here you can see a NTSC Console in 60Hz Mode the 0 Ohm Resitor gives GND to Pin64
Pin 64 of the nearby chip LSPC2-A2 9305 E27 sets 50 or 60Hz.
GND at Pin 64 -> 60Hz
5V at Pin 64 -> 50Hz
