Getting a Naomi 2 Running without a cab using original power supply, Please help.

Since my last post I got a multimeter to test the voltages.
The original voltages were

brown wire:
3.40

Yellow/Gold wire: 5.22

Red wire: 12.20

I adjusted them
down to 3.30 and 5.10 respectively and got no video (after the Naomi 2 logo). On
one forum, they recommended 3.35 and 5.15, that makes the system cycle boot
(Naomi 2 logo, black screen, Naomi 2 logo, black screen, and so on). What
voltages are the proper ones?

 

You took the voltage when the actual machine was connected?

 

The machine was on and in test mode when I took these measurements and adjustments.

 

Well Naomi 2 are notoriously picky and stupid. You need a bit over volt but not 5.22...

This is why I used ATX PSU always because it doesn't go crazy under the load of Naomi2. ATX PSU gives stable current.

 

Redid the ram and rom tests on the board. All of the Naomi 2 ram is good but the Rom Board Test shows all of VF4's roms being bad. Any clue why this would happen?

 

Broken buffer chip inside the cart, You should be able to enter game test mode though

 

Strangely enough, messing with the voltages makes some of the chips go back to being good while some stay bad, one time it was even down to 2 chips bad only (although nothing will make the game boot again). I guess the cart is the problem here. Would that account for all the problems I have had?

 

that is why I told you to find another cart and test the board sometimes carts go bad. Also don't mess too much with the power don't want to fry the board, leave it withing parameters 5.10 to 5.15 maximum.

 

Should the 3.3 be left at 3.30 or is the 3.35 better like some forum users have claimed?

Also I happen to have one of these:



It uses a db15 connector and is designed for old dos computers, would there be any way to wire this to Naomi, just had seen a pc controller sitting on the desk and thought of this.

 

Small update. I received Dead or Alive 2 Millennium and Project Justice Cartridges not too long ago. With the system running at 5.10 and 3.30 both games run just fine and rom checks pass on both flawlessly everytime with zero freezing. I am guessing either the vf4 cartridge was on its way out or was killed due to the previous operator turning the voltage too high.

Moving on: I purchased a net dim board on ebay, only problem is, when the net dim is plugged in the system, it displays no video at all. I tried some troubleshooting steps suggested on other forums such as only inserting the bottom board into the system without the top communication/network board. I get an error 22 which from what I understand means the dim board can not communicate with the top board. (which of course makes perfect sense if it isn't attached) The dim board test times out as well without the top board attached. The only problem is when the top board is attached, as I had said above, the system displays no video at all. I have tried cleaning the boards and everything but can not get any video from the system with this board in. Could this possibly have anything to do with the bios? (current bios is EPR-23607A) Did certain usa Naomi 2 bios not work with gd-rom or net dim boards? Could it be a problem with the ram dim on the dim board? Any help would be appreciated so I can get the gd-rom up and be playing Virtua Fighter 4 Final Tuned.

 

From what I remember, I had to buy a new BIOS when I ordered my NET dimm.
You might possibly have another problem though, on mine the pins got lifted a bit and messed up from the plastic connections and I managed to eventually get my NET dimm board locked in, but if I remove it again, loads of pins will touch and it'll mess up again so you could have a quick look to see if it's done that on yours?

 

Your bios is good to run dimms and gd roms. It has to be another problem.

 

I have cleaned the dimm and all the contacts are fine but I can not get any video at all. Are you sure that my bios would work with a net dimm, I had read somewhere that some of the earlier bios did not work with the net dimms.

Any clue what other problem it could be?

Could the ram be at fault?

 

I would say that connection between the mobo and netdimm is at fault ; just clean it and insert it carefully, should be OK.

 

Since making these posts I have gotten my hands on a regular Naomi dim board. It was only a 1.02 version. Figuring the bottom board of the net dim was good and the top board was at fault I put the bottom board on the regular dims top board and it works, even for playing Virtua Fighter 4 Final Tuned since the net dim had 3.17. Strangely enough, when the jumper from the net dim top board is set to network mode the system displays and it seams to work. That top board for the net dim just not allow the system to display video when in gd-rom/scsi mode. Strange?

 

Hi , one cool thing to do is connect Dreamcast joystick to the Naomi (1 or 2) , you can get those almost free at goodwill stores.
Use the maple bus for Dreamcast controller on CN6 & 7.
I have the wiring here somewhere I'll post it as soon as I find it.