Naomi unit problem

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landisama
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Joined: September 20th, 2016, 3:09 pm
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Naomi unit problem

Postby landisama » February 19th, 2017, 11:14 pm

Hi guys,

I have a Naomi unit that worked like a charm until a few days ago. It was running a game in demo mode and suddenly it entered into the dip switch menu. The test/menu buttons could not be used to exit this menu. I shut down the unit and restarted it. Sometimes it freezes after the Naomi logo or sometimes it gives me this screen when started up. Does anyone know what the problem is? Can it be fixed?
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Asure
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Re: Naomi unit problem

Postby Asure » February 20th, 2017, 9:59 am

Something going on with the Naomi itself, or the I/O board.
There is a USB style cable that plugs into the front of the Naomi. It is connected to the I/O board which sits in the metal tray in the middle, below the control panel/monitor surround.
You need to remove the monitor surround to see it, as the tray it sits in is partly covered by it. Here's a nice clean picture of one:
Image

The error itself is strange:
If the cable is broken, there's no I/O visible to the Naomi mainboard in the bottom of the cab.
If the I/O is dead, it would not register (the 'Sega Enterprises bit' would not show at all.)

Remaining options
- Unlikely: Naomi board side has issue(s) registering the I/O
- Likely: The i/o board is partly broken (some short on the board) and not reporting back all data needed by the Naomi mobo.
It is detected, but not showing any bits, inputs/outputs etc. (it should show some..)

Most probably the I/O has an issue. I would remove the monitor/upper surround and see if there's any spilled drinks or stuff in the tray.
It has a plastic flap to prevent this, but stuff can still seep below the board and cause rust.
landisama
Posts: 30
Joined: September 20th, 2016, 3:09 pm
eBay: cameliacomicfan
Initials: AND
Location: Bucharest

Re: Naomi unit problem

Postby landisama » February 20th, 2017, 2:11 pm

Thanks for the fast answer.
I replaced the Naomi by a Naomi 2 unit and the game works very well. I think the Naomi 1 has problems and not the I/O board. The Naomi is quite noisy due to the back fan. Could an eventual malfunction of the fan to have been overheating the board and break it? When I checked it it was warm (but not alarmingly warm)
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nem
Posts: 663
Joined: August 17th, 2008, 6:59 pm
Location: Finland

Re: Naomi unit problem

Postby nem » February 20th, 2017, 3:36 pm

It's possibly a capacitor issue. You would have to replace the caps. They're all SMD ones and there's some two dozen of them.

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