black screen naomi2 but gmz working!!WHERE R VIDEO IC ON MB

OldFoo · Post by **OldFoo** » Sat Jun 28, 2008 6:23 pm

I believe the video IC is underneath the fan.

OldFoo · Post by **OldFoo** » Sat Jun 28, 2008 8:15 pm

trouble is these are bga ic so you will not be able to replace it anyway-unless of course you have ?20,000 worth of bga rig hanging around

OldFoo · Post by **OldFoo** » Sat Jun 28, 2008 11:33 pm

It's better to get another system. I don't think you can fix it yourself.

OldFoo · Post by **OldFoo** » Mon Jun 30, 2008 2:54 pm

thx for the diagnostic

it smells bad....

is it possible that this one don't work anymore without any burnt lines, or other burnt components ???

OldFoo · Post by **OldFoo** » Tue Jul 01, 2008 2:21 am

IC's have internal components and thin leads that go to the pins on the outside. It is quite possible that the IC has burnt out internally (like a fuse) and show no outward signs of damage.

OldFoo · Post by **OldFoo** » Sat Aug 09, 2008 2:47 am

OK,

I have a NAOMI system here with the same symptoms.

If you follow the traces back from the I/O board (I don't know the exact terminology for that vertical board with all the connectors) to the main board it goes like this:

I/O board --> R354S / R339S / R340S --> C65 / C64 / C63 --> IC41

The 3 resistors are 0 ohm resistors, kinda like fuses if you will. The caps are 220uf @ 16v surface mount. I listed three of each as there's one each on each of the red/green/blue lines.

IC41 is the 315-6145 chip. It's a small 56 pin surface mount IC near the red and green LEDs. It's the DAC that converts the video output to analog for the monitor.

If you have a logic probe you can check the inputs and outputs of the chip. On the board I have here to repair it has inputs but no outputs. Also, the chip gets VERY hot. I'm waiting on someone from the Neo-Geo forums to send me a Dreamcast to pull the chip from.

RJ