Model 3 power

[Kev A]

Currently looking at replacing the power supply's in my Sega Rally 2.

The original PSU has obviously died at some point and has been replaced with 2 PSU's, one supplying 3.3v and another supplying 12v and 5v. with GND connected between them.

I haven't seen anything like this before and I cant imagine its recommended. I would like to replace it with something else.

All of the connectors have been chopped so I'm not tied to using an original model 3 PSU.

I know some people recommend Naomi PSUs but these are getting on a bit now, and don't seem too easy to find.

Have also considered a new ATX PSU, I have an old one with a voltage adjustment pot inside so the 5v can be increased slightly, I'm using it on my model 2 test bench but I cant find any new ones that have this feature or if they do its not mentioned anywhere.

Any advice welcome, are non adjustable ATX PSU's ok or is it best to look out for a Naomi PSU???

Cheers guys

 

[robotech]

You can use a pc power supply i have one on my test setup
But you cant ajust the 5v

I would go for a sun psu

 

[channel27]

I found the same thing (2 PSUs, one for 5/12v and the other for 3.3v) in a cab with a Naomi and Virtua Striker 2 in it. I replaced it with a Naomi PSU as it just felt odd...

My Virtua Fighter cab has a Model 3 PSU in it which I run Model 1, 2 and 3 stuff off...

And my test bench uses an ATX power supply...

So a mixed bag, really!

I'm going to swap the ATX PSU on the test bench with a Model 3, as the ATX PSU was the only thing to hand at the time and has no adjustments.

I've never actually run Model stuff off of a Naomi PSU before. I assume it can handle it?

 

[robotech]

I have had model 3 cabs with the naomi sun psu allready fitted
With the conversion cables no issues at all

 

[Kev A]

Relieved to hear others have had the 2 power supply setup before, I cant think of a reason it wouldn't be ok, but like you I find it strange.
Think I will keep an eye out for a Naomi PSU on here.

Kev A2018-11-15 17:26:50

 

[obcd]

A good ATX power supply should work fine as well. Newer ones have a sense wire on their most critical 3V3 power rail. So the cable losses should be compensated automatically ensuring 3V3 arriving at the game boards. You will need to gnd the power on input so that the supply turns on directly when it's powered.

 

[Kev A]

Cool thanks for the advice guys, decided to go for a Naomi Sun PSU in the end.
As the connectors have been chopped and terminated with spade connectors and as the cab wiring has more 5v and 3.3v wires than the Sun PSU I'm going to connect the two together through a distribution block, (a bit of wood with bolts) That should give the flexibility to go to an ATX PSU in future should the Naomi PSU die without having to re terminate.

 

[Sbdesign]

Ive got a similar issue but slightly different

Sega Rally 2 deluxe.

Model 3 power replaced with a JVS (doesn't look same as naomi)

They have the conversion cable converting to model 3 plugs.

ISSUE: the conversion cable doesn't have all the cables going to the block connecting to the machine,

EG: Extension cable has a 8 pin block going to cab, but only 4 wires populated. The connection that goes in it from cab has all 8 populated. This means that later down the chain there is 2x 4pin connectors that are identical, and 1 doesn't have power. 1 powers the DSB2 bd and the other the FFB bd, so currently can only have 1 or the other.

Does anyone know if I can just bridge the connector so it powers both?

 

[robotech]

Pretty sure i had to do this on my scud race cab it had the jvs sun psu conversion but the cables had not enough wires passing through to power the dsb 1 /rear cabinet fan
So i added some

 

[Sbdesign]

what can go wrong I was thinking...
Then realised any answer would be a presumption... Im no expert with good enough knowledge on this.

Do you know...

Is it safe to do?

will it draw additional amps through the connector and possibly damage anything?

I have a sega rally twin, but bought a deluxe a while back that was knackered.

I need to switch the sh*t LCD for a custom rear projector yet (done it on my megalo 50" with happy results)

I have managed to get audio working but some fuses end up blowing, I think there is 6 speakers on the deluxe.

The force feedback board seems goosed, but don't mind using my twin parts (as this will go into storage when deluxe working and replace it in my setup) but not until I can confirm what ever caused the damage originally is ironed out, otherwise I'll be damaging my good parts, which is not a good idea.

 

[Sbdesign]

we should create some sort of groups on here, as I keep seeing the same names for model 2/3 wants/faults/fixes/questions.
Is it not time on this forum to have further sub sections for arcade types?

 

[Kev A]

Good point about the sub sections, would make it easier to track down relevant info, just searching for model 2/3 brings up loads of unrelated info.

How about bridging the connections with a multi meter first, see how much additional load the DSB2 will be pulling?

I have just ordered the cables and connectors (bloody expensive) to make up my harness for the Sun PSU, the 1.5mm wire I'm using is rated for 13 amps, so a single cable should be able to handle more power than the PSU can provide.