What's new
By:

Naomi 2 - GPU Fans Not Spinning

T

tika

Enthusiast
Joined
Apr 6, 2019
Messages
158
Reaction score
52
Location
Australia
Hi all, just wanted a sense check - if the 2x GPU fans on Naomi 2 mobos are not spinning (ie: filled with gunk), will the Naomi 2 boot/display video output at all?

The backstory is that I've recently purchased a Naomi 2, and didn't boot first up, and upon checking the GPU fans, they're filled with gunk of sorts and wont spin at all. I've also checked the voltages on the PSU (I'm using a 750w ATX PSU - that's all I had lying around), on the mobo and the fan headers, and the 5v rail is very close to +5.0v
 
nem said:
Naomi won't boot if the fans on top of the processors aren't spinning. It's a safeguard.
Click to expand...
Thanks for the confirmation - I suspected as much as I thought I had read it somewhere before.

Is it possible to fool the Naomi 2 in thinking the fans are OK just so I can see if it POST/boots to a screen at all? Can I connect any 5v fan to the 3-pin header on the Naomi mobo or something else to get it going?
 
tika said:
Thanks for the link mate - I've checked my Naomi 2 with the ATX PSU I have connected to it (Corsair HX 750i) and it's a solid 3.15v at the JST plug during power on and afterwards
Click to expand...

That's low. It should be 3.3V.

tika said:
Can I connect any 5v fan to the 3-pin header on the Naomi mobo or something else to get it going?
Click to expand...

You can try, but not all fans will work.

See this thread for working replacements:

Derick2k

Thread 'Replacement Naomi Fans?!'

Hey Folks,

I am looking for alternate replacement fans for the Naomi 1 & 2 boards.

I got replacements for the case fans, I went with Gelid Silent 6 fans.

But the CPU far are proving a little more difficult to source, anyone know of some solid replacement fans for the cpus?
  • Like
 
nem said:
That's low. It should be 3.3V.



You can try, but not all fans will work.

See this thread for working replacements:

Derick2k

Thread 'Replacement Naomi Fans?!'

Hey Folks,

I am looking for alternate replacement fans for the Naomi 1 & 2 boards.

I got replacements for the case fans, I went with Gelid Silent 6 fans.

But the CPU far are proving a little more difficult to source, anyone know of some solid replacement fans for the cpus?
  • Like
Click to expand...
That's good to know - thanks! I've tried a different ATX PSU (PicoPSU) that I had lying around, and it outputs a solid 3.3v on booting up the Naomi 2 and once it's running. I tested the 12v and 5v rails, and with the 5v rail being 4.97v, and the 12v rail coming up as 11.87v - are these close enough to boot the Naomi? If they are, then I'm suspecting the janked up GPU fans are preventing the hardware booting up.

Either way I'll grab a couple Noctua NF-A4x10-5V fans to test if the mobo actually boots with the GPU fans spinning
 
5V is a bit low, but it should boot. 12V doesn't matter. Ideally you would have an arcade PSU that you could manually adjust the voltages with.

Try replacing the fans.
 
So an update: I bought 2 new GPU fans (Noctua NF-A4x10-5V) and switched the pins over so they work, but no video output from the Naomi via the VGA port on the device. I checked the CR2032 battery, and it was dead so I replaced it, to no avail.

I connected a JAMMA to JVS adapter, and into my supergun, and still no video output from the Naomi, so I'm thinking it's dead.

I have a Virtua Tennis cart in it to test - will the Naomi boot/produce video output without a game plugged into it?
 
tika said:
will the Naomi boot/produce video output without a game plugged into it?
Click to expand...

Sure will. It will boot an error screen and you can enter the service menu.

Obligatory reading:

doccaz

Thread '[Repair Log] Naomi 2 won't boot'

Hi all,

I acquired a Naomi 2 at a japanese auction, and besides some heat marks and scratches on the plastic case, appears to have been untouched. Even the screws had that "factory torque" when I opened them.

I inspected the motherboard on the microscope and found no corrosion at all. All capacitors appear (visually) to be okay. The only issue I could find was that the wires to the middle GPU fan were "chewed up" pressed between the edge of the case. But they all checked out okay with a continuity test, just added some tape to them. Looks like someone at the factory was in a hurry and...
  • Like
 
Any sound?
black screen is usually bad ram but could be many things.

If you put a Naomi 1 game in it will disable the extra naomi 2 ram and try to boot so try that first.

Also make sure you wiring on the new fans is 100% including the 3rd sense wire for the fan speed
 
And wait a bit ... some noamis take longer to boot. (30-60sec)

check the back / front of the i/o board if there is maybe a burned trace on the VGA connector line

Is the dip switch (on the i/o) set to 31khz? :)

the system fan is spinning?

Is your monitor capable of picking up the signal (i had some TFT Panels where i could not get an image)

sadly in most cases with black screen it is one of the rams :(
 
nem said:
Sure will. It will boot an error screen and you can enter the service menu.

Obligatory reading:

doccaz

Thread '[Repair Log] Naomi 2 won't boot'

Hi all,

I acquired a Naomi 2 at a japanese auction, and besides some heat marks and scratches on the plastic case, appears to have been untouched. Even the screws had that "factory torque" when I opened them.

I inspected the motherboard on the microscope and found no corrosion at all. All capacitors appear (visually) to be okay. The only issue I could find was that the wires to the middle GPU fan were "chewed up" pressed between the edge of the case. But they all checked out okay with a continuity test, just added some tape to them. Looks like someone at the factory was in a hurry and...
  • Like
Click to expand...
Thanks for the info and link - I've had a good read over the post and have checked the voltages at the PSU and the various voltage test points on the Naomi 2 mobo - all look to be good (also very similar to the voltages in the thread you posted).

I've checked the voltage on the VGA port on pins 1 and 6, and am seeing ~0.0v there. I checked the pings 1 (Red, 2 (Green) and 3 (Blue), but they all show 0v. Interestingly the H-sync (pin 13) and V-sync (ping 14) pins show +5v when the console is powered on.

I've also tried both the RAD2x and a GBS 8220 (VGA) device inline from the Naomi VGA port to the monitor to check if there's a some scaling/sync issue with my monitor, but still am not seeing any video output using either of these devices in 15k or 31k video output mode. Sound output is also no existent.

After a few mins of being on, the various IC's are warm to the touch, but sadly not seeing any video/audio output
 
MickyMac said:
Any sound?
black screen is usually bad ram but could be many things.

If you put a Naomi 1 game in it will disable the extra naomi 2 ram and try to boot so try that first.

Also make sure you wiring on the new fans is 100% including the 3rd sense wire for the fan speed
Click to expand...
No sound at all from the Naomi 2 - I've used different speakers to check, but still no audio output from the N2.

I can verify that the new fans are working and the sense wire is in the correct position. Not sure if my monitor can handle the Naomi video output, but have tried multiple in-line VGA devices between the N2 and monitor, just incase there's something going on with the monitor. I've also tried different monitors and 15/31k video output modes, but still nothing is displayed.
 
Orakelschaf said:
And wait a bit ... some noamis take longer to boot. (30-60sec)

check the back / front of the i/o board if there is maybe a burned trace on the VGA connector line

Is the dip switch (on the i/o) set to 31khz? :)

the system fan is spinning?

Is your monitor capable of picking up the signal (i had some TFT Panels where i could not get an image)

sadly in most cases with black screen it is one of the rams :(
Click to expand...
It's looking like it's the RAM after trying multiple monitors, video settings and no audio output from the N2. In saying that, I checked the voltage between pins 1 and 6 on the VGA adapter, and it read 0v. Checking pins 2 and 3 to 6, also showed 0v. I traced the pin 1 on the VGA adapter and it buzzes out to ground - so it may have a short in the filter there. Are these known to fail?
 
I took some pics for posterity for the various JP points on the N2 mobo. I also took a few pics of the N2 mobo underside - looks like there was some work/reflow done. Is this normal for a stock N2 mobo out of the factory, or does the below indicate some work was done on the board previously?
 

Attachments

  • JP1.jpg
    JP1.jpg
    163.8 KB · Views: 3
  • JP4.jpg
    JP4.jpg
    158.4 KB · Views: 3
  • JP7-12.jpg
    JP7-12.jpg
    159.1 KB · Views: 2
  • Mobo Back 1.jpg
    Mobo Back 1.jpg
    265.3 KB · Views: 2
  • Mobo Back 2.jpg
    Mobo Back 2.jpg
    251.3 KB · Views: 3
  • Mobo Back 3.jpg
    Mobo Back 3.jpg
    228 KB · Views: 3
  • Mobo Back 4.jpg
    Mobo Back 4.jpg
    242.5 KB · Views: 3
This looks like very old flux - And the flux is on places were normally repair would not have been done (but i may be incorrect on this)

If you still get a black screen it is 99% one of the rams.

1753008060422.png


I would remove this Supercap (and before that please receck if this is the supercap) and check if some of the traces around it are gone

Btw are you running with stock bios?
 
You must log in or register to reply here.
Back
Top