UPDATE Naomi 2 + GD Rom - Power Issues

LegoSlug

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Dec 10, 2012
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864
Hello all,

I recently picked up an initial twin d set. One of the 2 sides does not appear to be working properly.

I am trying to find out what the ideal range is for the 5v, 3.3v, and 12v lines.

Both of my sun power supplies seem to be running hot. I turned down both the 5v and 3.3v lines on the non-working Naomi 2 and they are still reading at or above 5v and 3.3v. The 12v line is running above 13v.

The working side is similarly reading on the high side. I understand that the Naomi 2 will not run properly below 5v and 3.3v, but at what point are they getting too much juice? I can't find any concrete info online. I know that it is better to run a little above 5v, but I think 5.3v might be too high.

I am thinking that because the twins were on location, on for hours a day, maybe the hot power supply blew out the motherboard. :scratch:

This would mean that it is only a matter of time until the other motherboard shares a similar fate.

Any ideas? I'm thinking I should recap the sun psu's regardless. They seem to be running hot.

However, it would be good to know what voltage people normally run their naomi 2 gd rom setups at for reference.

Just trying to trouble shoot the non-working side. I have confirmed that both monitors are working. I tried hooking up a different monitor to the non working side. No image. No sound as far as I can tell.

I see a light on the mobo, I can hear the gd rom spinning. Maybe it's just the filter board? I seemed to have read something about it online. Maybe I can swap it from a Naomi 1?

Any ideas welcome.
 
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LegoSlug

Over Top Auto Mechanic
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Dec 10, 2012
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I have turned down my psu as low as they will go. The voltages seem way too high. I ordered a spare sun psu, as well as caps to rebuild the current psu's.

Out of curiosity, I checked all my cabs and my New Net Cities were also running hot, although not as bad. I turned the voltage adjustments all the way down and they are still on the higher end. They can't go under 5v for example. I am wondering if as the psu's wear out this is a common problem.

Also noticed my Astro City was having a similar problem. I turned the voltage all the way down and I am still reading 5.2v at the jamma edge. Not going to be leaving that cab on from now on. My neo geo cabs were fine. My Crazy Taxi was fine as well, although it has a sun psu too, I am pretty certain it is a different model, since it has a blue led light instead of red like on the NNC's.

If rebuilding the sun psu's fixes the problems... I'm going to end up rebuilding 5 psu's. Anyone had this happen with any of their power supplies?

As a PSA, check your voltages!
 
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madman

Blame madman, You Know You Want To.,
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I assume so, but all those voltages were under load w/all the NAOMI shiz hooked up?
 

radiantsvgun

They call him Mr. Windy
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Sep 29, 2007
Posts
1,687
I have turned down my psu as low as they will go. The voltages seem way too high. I ordered a spare sun psu, as well as caps to rebuild the current psu's.

Out of curiosity, I checked all my cabs and my New Net Cities were also running hot, although not as bad. I turned the voltage adjustments all the way down and they are still on the higher end. They can't go under 5v for example. I am wondering if as the psu's wear out this is a common problem.

Also noticed my Astro City was having a similar problem. I turned the voltage all the way down and I am still reading 5.2v at the jamma edge. Not going to be leaving that cab on from now on. My neo geo cabs were fine. My Crazy Taxi was fine as well, although it has a sun psu too, I am pretty certain it is a different model, since it has a blue led light instead of red like on the NNC's.

If rebuilding the sun psu's fixes the problems... I'm going to end up rebuilding 5 psu's. Anyone had this happen with any of their power supplies?

As a PSA, check your voltages!

Sounds like your PSUs need some recaps. The SUN one in my new net was having the same problem, swapped it with another psu and its fine.
 

LegoSlug

Over Top Auto Mechanic
Joined
Dec 10, 2012
Posts
864
I assume so, but all those voltages were under load w/all the NAOMI shiz hooked up?

I took some voltage readings from the filter board. Still too high. Is there a better place to take readings?
 

skate323k137

Professional College Dropout
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Jan 7, 2013
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The main one to watch for NAOMI is that 5v doesn't go over 5.2 at the filter board. 5.15 is fine. I run mine around 5.10 and 3.33 ideally.
 

LegoSlug

Over Top Auto Mechanic
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Dec 10, 2012
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The main one to watch for NAOMI is that 5v doesn't go over 5.2 at the filter board. 5.15 is fine. I run mine around 5.10 and 3.33 ideally.

I'm curious to know what model power supply you are using. If it's the SUN psu which version is it?

All my PSU's which are giving a high voltage are model 400-5397-01, which all have a red led light. I just bought a spare psu, with model number 400-5397 and the voltages are reading 3.4v and 5.09v with the adjustments all the way down. The powers supply in my crazy taxi also has a blue led, so I need to confirm the model number.

Maybe certain versions are not as good?
 
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LegoSlug

Over Top Auto Mechanic
Joined
Dec 10, 2012
Posts
864
So I just recapped one of the PSU's model 400-5397-01. Hooked it up and the readings are as follows on the lowest possible adjustment:

3.3v reads at 3.6v
5 reads at 5.35v
12 reads at 13.31

So the recap basically did nothing to fix my SUN power supply.

Any ideas? I dunno what else to do.

Update: FML I think it's my multimeter
 
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