Sega Naomi video problems

[bravesirchris]

This is my first sage Naomi, and right away i've got this.
I'm thinking it got to be a issue with the graphic board/chip. any one have any ideas.

 

[Hydreigon]

All I can say is do a RAM test and send a screenshot of the results. I'm praying it isn't BGA failure on that GPU chip.

 

[skate323k137]

Have you tested on any other displays, preferably an old PC CRT?

 

[bravesirchris]

I plug the machine original CRT back in and i've still got the same. i'm thinking it got to be a problem with the Naomi

 

[skate323k137]

I plug the machine original CRT back in and i've still got the same. i'm thinking it got to be a problem with the Naomi

that's a shame, you're almost certainly right that it's the NAOMI. You can double check your voltages but I highly doubt that's going to fix this one.

 

[Hydreigon]

So where is the RAM test I am waiting for? That is the best way to determine a faulty Naomi unit.

 

[bravesirchris]

I tried to do a ram test and the machine just froze up,let it like that for a hour then turn it off.

 

[Hydreigon]

I then suggest replace the graphical ram at IC16. Also check voltages too, 5v and 3.3v.

Edit: Original ram chip used was a HY57V161610DTC-8, 2 Banks x 512 Kbits x 16 (16 Mbit) ram, TSOP-50. Best replacement I can think of is this: https://www.mouser.com/ProductDetai...4dzSHpcLNggeRXkNaSMXj9ow9k9wy0juh36L0I/SPwg==