Naomi Dimm Board Not Working

[ThisGuy]

So as the title states I received a Naomi dimm board I just bought to try to set up netbooting that is not working in my naomi 1 unit.
My bios is usa revision E and dimm board is on v3.17

When currently trying to boot naomi with dimm board all I get is a black screen

Ive tried the following in hope to get it working:
- checked voltages
- cleaned all contacts
- tried with jumpers set for gdrom and netboot
- removed case to get better connection
- with/without daughter board
- switched memory slot
- removed memory
- with/without 0 key

Regular cart games work fine

Any ideas on what I can do to fix this? Is there something else I can try? Or is this thing dead?

 

[skate323k137]

Update your bios 1st. E supports gdrom dimm (or should) but is still an old chip.

 

[ThisGuy]

Update your bios 1st. E supports gdrom dimm (or should) but is still an old chip.

Thank you I actually just ordered a new bios and 0 key in case one I had were bad.

 

[penrhos]

are you using a sun psu or a Jamma->jvs adapter?

Adapters don't output enough amps to run a dimm board.

 

[twistedsymphony]

When currently trying to boot naomi with dimm board all I get is a black screen

note that it can take a good 30 second for the NAOMI logo to show up when booting with a DIMM board. So don't just power it on and power it right back off again when you don't see the logo right away.

checked voltages

for a DIMM board the 3.3V is the most important. I tend to adjust it to 3.4V as measured on the filter board connector.

 

[ThisGuy]

are you using a sun psu or a Jamma->jvs adapter?

Adapters don't output enough amps to run a dimm board.

I am using a sun psu

When currently trying to boot naomi with dimm board all I get is a black screen

note that it can take a good 30 second for the NAOMI logo to show up when booting with a DIMM board. So don't just power it on and power it right back off again when you don't see the logo right away.

checked voltages

for a DIMM board the 3.3V is the most important. I tend to adjust it to 3.4V as measured on the filter board connector.

I let it sit about 1-2 minutes with black screen because I had read that it can take around me 30 secs. Still nothing

I will try to adjust voltage to 3.4 later and see if that help. I’ll post what happens later

 

[skate323k137]

5.10 and 3.33 should be fine. Both are adjustable on the Sun

 

[ThisGuy]

So I made some progress. I adjusted voltage to 3.4 and now it’s booting. Not sure if it was voltage or reseating for the 50th time but either way it’s now booting.
So I guess my bios does not support netbooting though since network settings option does not show in settings menu.
I’ll have to wait till I get new bios to go any further. I though revision E bios was good enough....I guess not

Thank you everyone for the help

 

[jassin000]

I was using Jorge's multi cart BIOS, but I believe his is based on the H revision (aka H should work)?

 

[twistedsymphony]

I adjusted voltage to 3.4 and now it’s booting.

the Net DIMM is really hungry for that 3.3V and by the time it passes through the main board and those crappy cartridge connectors the voltage drop inside the Net DIMM can be significant. So that's why when people have problems with the Net DIMM not booting I usually recommend running the PSU a little hot on the 3.3V line.

 

[xodaraP]

It's a problem of current (amps) which is why you need a strong PSU like the Sun to power it, cheap PSUs just can't take the current draw so the voltage drops.

The only way to compensate is to increase the voltage which then increases the overall power output (watts) as you can't turn up the amps on an arcade PSU

However you need to be careful here because if the voltage is higher than the amps able to carry it, the excess power is converted to heat, or travels the path of least resistance (destroying whatever ICs, traces or other components that aren't able to cope with the excess)

NAOMI boards are stupidly picky about the 3.3v - on my Cyber Lead if it's not at 3.3v exactly, it black screens

 

[twistedsymphony]

I've never not used the official SUN PSUs on my NAOMI and I typically have to run them at 3.4 to get them to boot. Granted there are 2 different versions of these PSUs with two different AMP ratings, so this could just be a symptom of the weaker NAOMI PSUs.

running without a case and measuring the voltage on the DIMM board itself it comes in at 3.3V exactly.

I'm using NAOMI/SUN PSUs on my VOOT cab for Model 3 as well. One side uses the higher AMP rated NAOMI PSU and never had any problems , the other side used the lower amp rated NAOMI PSU and would occasionally lock up, until I pulled the lid and measured voltage on the PCB directly and cranked it up to compensate for the voltage drop (so that it measures 3.3V exactly at the chips). It's been rock solid since but measuring at the filter board the voltage looks really hot.