First Naomi Cabinet

[OldFoo]

I've been lurking these forums for a while now gathering some info, and today I finally purchased a cabinet I had been looking for.



Today I bought House of the Dead 2, it has a dead psu though.

Is it really as simple to fix as modifying an atx pc power supply via this guide:

http://www.sega-naomi.com/forum/viewtopic.php?t=2301



Then hooking it up to the cabinet? I'm wondering if there are any extra things I should be looking out for when going about this?



I do have a spare 600 watt pc power supply, not sure if that will work though.



Any thoughts or suggestions would be much appreciated.

[OldFoo]

There are two schools of thought. Some would say it is well worth it to just get another Naomi supply. They are relatively easy to find cheap on eBay starting under $20 quite often. A true arcade supply typically has adjustable line voltages. Low voltages can cause strange symptoms, especially the 5 volt line with a GD/DIMM setup. Finally a stock supply will have the right connectors for hassle free connection.



If you do go with a PC PSU I would recommend a good quality supply (over/under voltage and short circuit protection) and match the specs to make sure it exceeds the originals. While 600 watts is more that the original, power supplies are rated at a current capability per voltage rail. Some power supplies provide multiple separate rails at lower amperage rating versus one rail with a higher rating. In a Naomi setup you would barely use any of the wires/rails so a combined higher rating does you no good if the one rail you use (itself) is insufficient. You should look for at least 3.3V 12A, 5V 10A, and 12V 2A.



I am new here but I?m sure some of the veterans can chime in and give you good advice based on their experiences.

[OldFoo]

My problem has become more complicated.



Well... its not the psu that is the problem, its something else.

Just checked it with the multimeter, and i'm getting normal voltages all around.

I've got no video and no sound, i've tried two arcade monitors.



The mainboard looks very clean, I saw in another thread something about looking for leaking capacitors and stuff. I don't see any obvious problems with it. So at this point i'm thinking either the Filterboard or mainboard itself?

Any suggestions would be much appreciated.

[OldFoo]

Well since I am sure you already checked the dip switch positions and you say no sound either it does not sound like good news. Another red flag is that you say the motherboard is clean. When you pick up an "as is" system that just needs some little something, a lot of times someone has already gone in there cleaned it all up and hit a dead end. Please follow proper ESD handling practices, In case you haven't tried yet, remove the CMOS battery and let the voltage dissipate. Check the battery since you have a VM. Remove and reinsert the BIOS chip making sure it is seated well, if you had a spare would say try swapping it. Also check the case fan manually turning to be sure it is not gummed up stuck or shorting. It is OK to leave the case fan disconnected while apart and testing. The chip cooler on the other hand must be free, rotating and well connected to the board. Observe its operation when everything is back together. If the motherboard does not get its tach signal it will not allow the system to run. Reinsert the CMOS battery and give it another go without the game plugged in to eliminate it as a possibility of failure. Worst case scenario you can get working Naomi motherboards all day long under $80 on eBay now days but don't throw away any bad boards. I myself am looking for a schematic for N1,N2 but have yet to find one. Maybe if I get one I can start offering repairs some day.

[OldFoo]

Thanks for the great advice, will try your suggestions when I get home from work. In the meantime, I have ordered another Naomi motherboard.



I'm just hoping the house of the dead 2 cart didn't die with this board, as I haven't seen many for sale and would imagine they aren't cheap.



Same goes for the bios, which i've heard is specific to this game.



But anyways, while i'm waiting for the board I will try what you've suggested.

[OldFoo]

A new motherboard did the trick, the game now runs pretty much flawlessly... for player1.



Player 2 gun trigger works in testing mode, i'm not getting any x or y readings though.

Swapped player 1 and two gun assemblies and the problems with that gun and wire persisted. Swapped gun sensors and neither worked.



This leads me to believe that the wiring and gun sensor on player 2 are not good.



Unless i'm missing something?

[OldFoo]

Do I need any extra hardware to run other gun games on my House of the dead 2 cab? Other than a bios, I know I need one of those for other games.

[OldFoo]

Do I need any extra hardware to run other gun games on my House of the dead 2 cab? Other than a bios, I know I need one of those for other games.

AFIAK with Sega games on the Naomi you'll be ok with the JVS board but you'll need a harness for stick based games.

[OldFoo]

What about something like ninja assault? Would it run on my house of the dead 2 cab if I change the bios? Or do I need some other hardware for it?

[OldFoo]

What about something like ninja assault? Would it run on my house of the dead 2 cab if I change the bios? Or do I need some other hardware for it?

Not sure about BIOS but you'd need the custom Namco gun board which needs a different light gun and a CRT screen.