What's new
By:
Filters

Naomi 2 - NetDIMM Won't Boot

nitelich

nitelich

Student
Joined
Apr 21, 2021
Messages
18
Reaction score
15
Location
USA
Been slowly testing this as I've had time over the past few months. I got the Naomi multiple years ago and the NetDIMM in presumably-working condition about a year ago. I didn't really start doing much testing until my Axunworks PSU appeared in the mail a few months ago.

Setup​

  • Naomi 2 with multibios or with USA bios
  • NetDIMM, 512MB, on version 4.01
  • Axunworks PSU Pro (voltages dialed in for both 3.3V and 5.0V)
  • I/O board is an MP12-IONA-SB, powered by a USB hub
  • Pi with NetBoot SD, powered by the same USB hub
Edit: I only have one Naomi 2 and NetDIMM to test with. My arcade collection isn't so vast as to include multiples. :unsure:

What Happens​

Normal cartridges work fine. I've run Powerstone 1 & 2 and an Ikaruga cart conversion. Before replacing the supercap, there was about a 25% chance for the Naomi not to boot at all, which made debugging difficult. But that's behind us, now.

With the NetDIMM, however, boot starts normally. I get a few seconds where a VGA signal is received (black screen, as before the Naomi logo appears), but then the VGA signal is lost. The NetDIMM Ethernet status LED continues to (slowly) blink after this, but there is no A/V activity at all. I've waited in this state for up to 2 minutes before powering down, in case it was just a long boot time that I was waiting for.

Because I can't even get to the Naomi logo screen, I can't enter the test menu or see any errors. So, while I have a Pi set up with NetBoot, it doesn't quite enter the debugging chain, yet.

Voltages at the filter board are within +/- 0.02V of what's reported by the PSU.

What I've Tried​

  • (Replacing the coin cell battery. I did this really early on because it was obviously dead. Only mentioning it for completeness.)
  • Reseating everything - the NetDIMM, the daughter board within the NetDIMM, the DIMMs themselves.
  • On the NetDIMM, I've tried with/without a ZeroPIC installed.
  • On the Naomi, I've tried all 4 regions of the multibios, and the plain USA bios.
  • I've tried both 15kHz and 31kHz. While my display accepts both, 15kHz stutters a bit, so I usually leave it on 31kHz.
  • I replaced the supercap on the Naomi mobo. While this had no effect on the NetDIMM, removing it revealed a small leak (cleanable; no apparent damage), so good time to replace it. There was an effect on the Naomi - it now powers up with noticeably more regularity (i.e. it hasn't failed to boot to cart since the recapping).
  • I completely recapped the NetDIMM. I didn't see any leakage, and no change in behavior.

Other Debugging?​

I'm not super familiar with the Naomi 2's schematics, testpoints, etc. Is there anywhere I could probe for voltages that might start narrowing down where the problem is?

I know there is a serial console on the NetDIMM, but have no knowledge of how to access it (or if it could even be accessed at this stage). Any ideas here?

Is the NetDIMM booting possibly longer than 2 minutes? Most posts I've read put its boot time up to 2 minutes...

Any other general tips for debugging this one?
 
Last edited:
It doesn't get to any variant of the Naomi screen.

I can confirm that the jumpers on the NetDIMM are set for network mode.

I'll will definitely look into the buffer chip. Thanks for the lead!
 
You must log in or register to reply here.
Back
Top