Naomi 1's booting, fans are on but no video/audio.

[varjak0]

Voltages are within 0.05 (or less). Brought 4 Naomi's sold as tested/working and they all power on and the fans run. All do the same thing, they will turn on and then not do anything - no audio or video. One Naomi gave me the splash screen sound but no video (then didn't do it again on subsequent tries to check voltage). Another seemed to "try" and boot as my monitor didn't go into standby mode as it did with the others.

All are running multi-bios 21576H. My guess is it's the eproms (as I've heard the multi-bios can cause issues) or a dip switch setting. Or shipping damage.

 

[Adrianlamande]

Are you using the vga port on the right?
Do you have the 15mhz/30mhz video output dip switch set correctly? Can you post pictures of your setup?

 

[varjak0]

Are you using the vga port on the right?
Do you have the 15mhz/30mhz video output dip switch set correctly? Can you post pictures of your setup?

There's only one VGA port on a Naomi 1 no?

I've tried with both the dip switch set to 15/30 respectively. I already packed things up for the day but I will get pictures.

 

[Adrianlamande]

Yes only one on the Naomi, sorry I was not in front of mine when I initially replied.

Check the dip switch setting as suggested. Check and double check the set up and voltages (especially the 3.3v), but don't go over 5.1v on the 5v as it can fry the buffer ICs and RAM, and make sure your test it on a vga monitor to rule out a non compatible display issue.

Typical reasons for a black screen if it is not a connection issue are:
1) A corrupted bios
2) The bios not being present
3) A dead supercap which is possible if it flew air mail to get to you.
4) The GPU fan not working.

The bastard (you will work out why it's called this soon) is located at C29 and can cause 1 and 2 as well as all sorts of issues similar to what you are experiencing (typically intermittent boot with a BAD IC29 degrades to no boot at all)
The bastard leaks causing absolute brutal destruction, particularly to the area around IC30 and IC31 which it leaks over and under. It cuts/corrodes traces in no time at all and must be desoldered and cleaned before the traces are re routed. This typically costs more to do than a Naomi is worth and I have a few dead ones lying around with this issue after they were never picked up by their owners after diagnosis.

Just incase a trace map

EEPROM (IC31) -> Altera (IC30)
Pin 1 -> pin 12
Pin 2 -> pin 11
Pin 3 -> pin 37
Pin 4 -> pin 4
Pin 5 -> GND
Pin 6 -> unused
Pin 7 & 8 -> + 5V

If you had video but no sound and the setup is all OK it is typically IC41 (RAMDAC HS)

They are the common issues that can cause similar issues to what you seem to be experiencing. Happy to look at your setup if you post photos and i hope it is just that. Enjoy the Naomi its a fussy thing but great when it's up and running

 

[varjak0]

The Naomis have new supercaps and the boards themselves look clean.

I'm going to be buying Happ PSUs and adjusting those to the JST connectors, in order to fully rule out the PSU being the issue (and to get a longer working life out of the Naomi).

 

[Adrianlamande]

Oh if you are running an ATX you really need the jST wired a certain way. If you just use a 20P ATX plug and match the wires 1 to 1 to the number of pins on the 2 Naomi power connectors you can have problems.

I made up a few ATX to Naomi cables this wat (1 to 1) to test them before offering them for sale. Myself and a few friends all had intermittent issues that were fixed by using 2 wires for 12v, 4 wires for 3.3v (the most important!!), 5 wires for 5v and 7 wires for GND. This is not my solution it belongs to Mitsu at Arcade Projects and out of respect for this I don't offer these for sale as he already does.

 

[varjak0]

Yea, I figured it was something with the PSU. Hindsight is 20/20.

Booting but no audio/video, its a pretty textbook "not getting enough juice". Happ PSUs should solve this issue as they're actually designed for this sort of thing.