Namco 246/256 power pinout and parallel circuit question.

[Kujako]

While I am waiting on some parts, I wanted to power up a 246 and a 256 system to make sure they work. I have a bench power supply with the required voltages, but not sure about the power pinout on the systems. Also, and possibly because I'm tired, I cant remember if hooking the same 12v (as an example) source to two pins on the Namco with different grounds is considered parallel or not and thus will result in a voltage drop... put another way, as I think there are two 12v pins on the Namco do they require different 12v sources?

 

[Franco23444]

The Namco system 246/256 can power up on a 200 watt power supply and I don’t think it requires separate 12 v power supplies to run the system efficiently, 5 v is what truly matters. Do you need the power pin outs for the system?

 

[Kujako]

The Namco system 246/256 can power up on a 200 watt power supply and I don’t think it requires separate 12 v power supplies to run the system efficiently, 5 v is what truly matters.

Fair enough, that's why I'm trying to find a pinout. My plan is to run it off my bench power supply which has 3.3v, 5v and 12v rails.

 

[Franco23444]

The pin outs for the Namco system 246 and 256 are color coded, 5v is red, 12 v is orange, and ground is black.

 

[Kujako]

The pin outs for the Namco system 246 and 256 are color coded, 5v is red, 12 v is orange, and ground is black.

Gotcha, so then looking at your pics a 246 (facing the unit left to right) would be ground, 12v, ground, ground, 5v, 5v and a 256 would be the same but upside down. Thanks. Still not sure about the whole parallel power issue. If I hook both 12v to the same power supply rail I worry about voltage dropping.

 

[Franco23444]

Gotcha, so then looking at your pics a 246 (facing the unit left to right) would be ground, 12v, ground, ground, 5v, 5v and a 256 would be the same but upside down. Thanks. Still not sure about the whole parallel power issue. If I hook both 12v to the same power supply rail I worry about voltage dropping.

Yes that is correct,12 v shouldn’t matter as much as the 5 v rail.

 

[Kujako]

Yes that is correct,12 v shouldn’t matter as much as the 5 v rail.

Thanks. Will give it a try. Worse case, the 12v voltage does drop and it doesn't work. Doubt anything will be harmed if I don't provide enough voltage.

 

[Franco23444]

Even is the 12 v line is off by a few 10ths, it should still be fine, These systems are very picky when it comes to the 5 v rail. 5.1 v should be good.

 

[Kujako]

Even is the 12 v line is off by a few 10ths, it should still be fine, These systems are very picky when it comes to the 5 v rail. 5.1 v should be good.

Wired (jury-rigged) things up, and got nothing... but it could be due to the system being bad. Have dip switches set to on/off/on/off for what should be test mode and 31khz output. Drive doesn't spin up. My understanding is that these systems won't boot without a drive detected? Not sure... I do get the red power led on the board, but could be missing something. Will try directly powering the hard drive and check the power out of the drive power connector.

 

[Franco23444]

Your wiring is correct, I see the red light. I see that you have a Namco super system 256 which only runs time Crisis 4. The main reason your system won’t do anything is because you don’t have the dongle plugged in. If you do have the dongle, plug it in the first slot and if it still doesn’t do anything, the hard drive could be bad. Without the dongle, the system is pretty much a brick. I’m not sure if this game will run without an i/O board though.

 

[Kujako]

Your wiring is correct, I see the red light. I see that you have a Namco super system 256 which only runs time Crisis 4. The main reason your system won’t do anything is because you don’t have the dongle plugged in. If you do have the dongle, plug it in the first slot and if it still doesn’t do anything, the hard drive could be bad. Without the dongle, the system is pretty much a brick. I’m not sure if this game will run without an i/O board though.

Correct re: 256. I do also have a 246, which is presenting the same issue. I can detect the 5v and 12v at the drive power connector, but the drive (CDROM or HD) never turns on. Almost seems like it's not pulling enough amperage. With the 246, the fan which is connected in series with the drive power also never spins up.

 

[Franco23444]

The question I have now is: do you have the dongles of the games to test your systems out? With out the dongles which look like a PlayStation 2 memory card, the system won’t do anything, but the system should at least turn on the hdd/dvd drive and the fans. Probably your power supply doesn’t have enough amperage, but I don’t think that’s the case. All the ground wires have to be connected as well. Try connecting all the black ground wires as well.

 

[Kujako]

The question I have now is: do you have the dongles of the games to test your systems out? With out the dongles which look like a PlayStation 2 memory card, the system won’t do anything, but the system should at least turn on the hdd/dvd drive and the fans. Probably your power supply doesn’t have enough amperage, but I don’t think that’s the case. All the ground wires have to be connected as well. Try connecting all the black ground wires as well.

I have a dongle for the 246/Time Crisis 3. But as I said, getting the same results. Going to put a pin in this. I appreciate the help, but I think I'm missing something fundamental. If the two 5v pins are splitting the single 5v input I think I'm only getting ~2.5v. However, I am tired and seem to not be able to remember my basic electronics right now... I also do have both a Naomi/JVS to System 2x6 and a System 2x6 JVS IO board on the way. So I may just wait it out (shipping can be exhausting these days).

 

[Franco23444]

I have a dongle for the 246/Time Crisis 3. But as I said, getting the same results. Going to put a pin in this. I appreciate the help, but I think I'm missing something fundamental. If the two 5v pins are splitting the single 5v input I think I'm only getting ~2.5v. However, I am tired and seem to not be able to remember my basic electronics right now... I also do have both a Naomi/JVS to System 2x6 and a System 2x6 JVS IO board on the way. So I may just wait it out (shipping can be exhausting these days).

Time crisis 3 doesn’t need a I/0 board to boot up, it only runs in 15khz and the dips are unresponsive without the appropriate I/0 board. I hope you get some good rest and I know you will be able to get these nice but picky systems to run.

 

[nem]

I can detect the 5v and 12v at the drive power connector

Measure the voltages with a multimeter. I bet they're low. Your wiring is technically correct, but you're using connectors that are likely making poor contact and insufficient wiring which will both result in voltage drop.

 

[Kujako]

Measure the voltages with a multimeter. I bet they're low. Your wiring is technically correct, but you're using connectors that are likely making poor contact and insufficient wiring which will both result in voltage drop.

Yeah, shoulda.... for some reason I ignored the multimeter on my bench and used a cheap ATX power adapter tester. I may have been over tired. At any rate, I've opted to just wait for my Namco JVS IO board, which has a power connector from the JAMMA and a JVS/Naomi power to Namco adapter. Both are on their way, but shipping is taking too long.

 

[Kujako]

Update: Looks like my 246 has a couple very dead capacitors. Still not sure what's wrong with the 256. The voltages at the drive power connector are right, but it's not providing enough juice to spin up the hard drive or power a CD drive.

 

[Kujako]

Got both systems to boot. The 246 has a dim video output, but otherwise is good to go. The 256 runs Gundam Seed at 2x speed using the 246 CDROM... including the intro song, which is weird but whatever.

 

[Franco23444]

Got both systems to boot. The 246 has a dim video output, but otherwise is good to go. The 256 runs Gundam Seed at 2x speed using the 246 CDROM... including the intro song, which is weird but whatever.

The 256 should have a set of pin headers that says 246+ and 256 mode on the right side. 246+ mode should make the game run as it’s supposed to. Currently it’s set to 256 mode, which causes 246 games to speed up or not boot at all. I know that the super 256 has the pin headers removed. You can wire up and solder on a toggle switch and see if anything happens. From what I heard, the super 256 will refuse to boot if set to the 246+ mode, but I’m not 100% sure though. Good to see that your systems turn on.

Edit: here is a picture of someone who modified their 256 to have a toggle switch for both modes. The location of the pin header should be present on your model.

 

[Kujako]

The 256 should have a set of pin headers that says 246+ and 256 mode on the right side. 246+ mode should make the game run as it’s supposed to. Currently it’s set to 256 mode, which causes 246 games to speed up or not boot at all. I know that the super 256 has the pin headers removed. You can wire up and solder on a toggle switch and see if anything happens. From what I heard, the super 256 will refuse to boot if set to the 246+ mode, but I’m not 100% sure though. Good to see that your systems turn on.

Edit: here is a picture of someone who modified their 256 to have a toggle switch for both modes. The location of the pin header should be present on your model.

I see the unpopulated three pin header alright. But at least from the parts side of the PCB it has no solder pads. I'll see if I can pull the motherboard and check the other side.

Edit: Got distracted by my ongoing PGM issues. Did pull the motherboard, and not sure I have pads for that jumper nor do I see any traces on the visible layers. In addition, I hooked things up to my cabinet and couldn't get the 246 to power on. The 12v was high, indicating that the circuit wasn't pulling the voltage down and the LED on the IO board flickered... not sure what the issue is. Will try powering it from a separate PSU later...

Side note: @Franco23444 or anyone else have any ideas why the 246 was dim? Thinking low voltage on some capacitors somewhere. May need to find a recap kit, but lots of SMDs in these things.