Naomi not displaying video

PCB problems and fixes
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SVTRondogg
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Naomi not displaying video

Post by SVTRondogg » December 31st, 2018, 7:09 pm

I'm brand new to both the cabinet and the Naomi hardware so please bare with me.

I recently picked up a Sega Blast City with the goal of installing a Naomi primarily, later on possibly swapping to a CPS2 setup. The Blast has the 001 harness inside.

I picked up a Naomi off eBay listed as tested/working. So far I have gotten it to power up, with both fans spinning and the green/red LED visible through the top vent.

However, I have yet to see any sort of video signal either through the Blast City monitor or my PC monitor. I have tried with the DIP #1 both off and on (31kHz/15kHz).

There is no JVS IO currently, but I am assuming I should at least see a Naomi boot screen or the IO error. Additionally, I shared photos with the gentleman who repaired my MVS boards, who indicated the supercap has leaked quite a bit. Not sure if that is enough to kill the board or not.

Attached are some photos in case I am doing anything incorrectly.


Thanks for any help!
Attachments
FB_IMG_1546278422060.jpg

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nem
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Re: Naomi not displaying video

Post by nem » December 31st, 2018, 7:54 pm

Check your voltages. Both 3.3V and 5V.

SVTRondogg
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Re: Naomi not displaying video

Post by SVTRondogg » December 31st, 2018, 8:31 pm

More attachments for reference.
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FB_IMG_1546279234431.jpg

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Re: Naomi not displaying video

Post by SVTRondogg » December 31st, 2018, 8:32 pm

Last one.
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Rossyra
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Re: Naomi not displaying video

Post by Rossyra » January 1st, 2019, 9:58 am

Check dipswitch 1 is off on the filter board (the board the cables plug into).
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leonardoliveira
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Re: Naomi not displaying video

Post by leonardoliveira » January 1st, 2019, 3:22 pm

Does it have any kind of sound?

I ask that because it could be processing the game but have a faulty video DAC IC. It is a rare occurrence but it does happen when faulty monitors zap the board through the RGB signal lines.
Image

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nem
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Re: Naomi not displaying video

Post by nem » January 3rd, 2019, 3:03 pm

leonardoliveira wrote:
January 1st, 2019, 3:22 MP
I ask that because it could be processing the game but have a faulty video DAC IC. It is a rare occurrence but it does happen when faulty monitors zap the board through the RGB signal lines.
Not rare at all. I've had it happen twice.

Did you check voltages yet, OP? If voltages are low it won't boot.

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Re: Naomi not displaying video

Post by SVTRondogg » January 5th, 2019, 7:44 pm

Quick update, I sent the Naomi up to Ken at IRepairSega (caught his name through this board) to check out the Naomi itself. I noticed the supercap had leaked quite a bit.

In the meantime, I verified the monitor and sound amp are good in the cab with my Dreamcast. :awe:

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Re: Naomi not displaying video

Post by SVTRondogg » January 5th, 2019, 7:48 pm

nem wrote:
January 3rd, 2019, 3:03 MP
leonardoliveira wrote:
January 1st, 2019, 3:22 MP
I ask that because it could be processing the game but have a faulty video DAC IC. It is a rare occurrence but it does happen when faulty monitors zap the board through the RGB signal lines.
Not rare at all. I've had it happen twice.

Did you check voltages yet, OP? If voltages are low it won't boot.
I’m picking up my multimeter from storage tomorrow to verify the JVS plug voltages.

I attached the pinout I found. Do the pin numbers read across horizontally?

Ex. 1 2
3 4

Or 1 3
2 4
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yosai
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Re: Naomi not displaying video

Post by yosai » January 5th, 2019, 8:28 pm

JSTPinout.jpg

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Re: Naomi not displaying video

Post by SVTRondogg » January 5th, 2019, 10:30 pm

yosai wrote:
January 5th, 2019, 8:28 MP
JSTPinout.jpg
Exactly what I needed to test it out, thank you!

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nem
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Re: Naomi not displaying video

Post by nem » January 6th, 2019, 1:38 pm

There's no point in measuring the voltage if there's no load attached. Only measure and adjust voltages if you have something connected to it.

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Re: Naomi not displaying video

Post by SVTRondogg » January 12th, 2019, 11:43 pm

nem wrote:
January 6th, 2019, 1:38 MP
There's no point in measuring the voltage if there's no load attached. Only measure and adjust voltages if you have something connected to it.
Noob question, how would I check the voltages with the plugs connected to the Naomi PCB?

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nem
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Re: Naomi not displaying video

Post by nem » January 13th, 2019, 12:37 pm

You just stick the probes inside the connector housing and touch the metal connectors. Brown wire is +3.3V, yellow +5V, red +12V and white is ground. Set your multimeter to DC voltage, put your red probe to any positive voltage, black to ground. I usually set voltages to 3.35V and 5.05V. 12V usually just runs the fans, so it doesn't really matter (and you can't even adjust it).

This said, some Naomi motherboards and / or carts are super temperamental. I had a Naomi 1 with a WWF Royal Rumble cart that I had to run at 5.15V, because it just wouldn't boot at a lower voltage.

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Re: Naomi not displaying video

Post by SVTRondogg » January 28th, 2019, 8:23 am

SVTRondogg wrote:
January 5th, 2019, 7:44 MP
Quick update, I sent the Naomi up to Ken at IRepairSega (caught his name through this board) to check out the Naomi itself. I noticed the supercap had leaked quite a bit.

In the meantime, I verified the monitor and sound amp are good in the cab with my Dreamcast. :awe:
Ken was able to repair my Naomi and all is well.

There was a loose ball grid array on one of the processors, likely from the trip over from Japan. In the meantime, I sourced a Capcom I/O and all is well (at least on the first 3 buttons, I am currently hunting for a kick harness).

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