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Namco 246 Low 5v Voltage

triforce7770

triforce7770

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Seem to getting 4.5v on the 5v rail on my namco 246 version b. I have the ide simulator,multi dongle,bladzx pi selector and rpi3b+.
Also noticed that i was not getting any video what so ever but getting power leds on jvs connector,dongle, and pi... Running on a k7000 25inch monitor also all dips are turned off.
It was working sorta with the orginal dvd drive trying to load tekken 4 but failed. psu im using is a 150watt molex style in a dynamo hs5 cabinet.
Also getting these errors on my pi giving a no monitor issue..

Also i plugged in other pcbs to my jamma connnector and getting 5.1 so theres something fishy going on this namco pcb.
 

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Yeah, the tiny slim power supplies won’t fully work with these systems because these systems are extremely power hungry especially on the 5v rail. You will need a beefy 200 watt power supply with a 5v pot to fully power the system properly. 5.0v-5.2v should be the sweet spot for the system. I have learned my lesson the hard way when it came to power them up. :)
 
Make sure the wiring from the PSU is thick enough to handle the current draw. Thin power and ground wires can lead to voltage drop.
 
Sounds like the problem right there. Gonna pick up a 200-250watt psu for it.
 
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ok so i found a betson 200watt power supply from twistedquarter. tried that and getting the same voltage. So i decided to remove my pi out of the equation and try to assign the multi dongle file and have only the iso of the image on the usb on my ide simulator. while trying to connect the dongle to my laptop with microsd the power is killed off ubruptly and and the psu is dead.... i dont know whats going on with my 246. maybe i shorted the connection to the reset wire to my namco selector???? previously tried this on my mortal kombat cabinet and it did the same thing but it was idling trying to load a game with only the multi dongle connected and no mod work was done previously
 
triforce7770 said:
ok so i found a betson 200watt power supply from twistedquarter. tried that and getting the same voltage. So i decided to remove my pi out of the equation and try to assign the multi dongle file and have only the iso of the image on the usb on my ide simulator. while trying to connect the dongle to my laptop with microsd the power is killed off ubruptly and and the psu is dead.... i dont know whats going on with my 246. maybe i shorted the connection to the reset wire to my namco selector???? previously tried this on my mortal kombat cabinet and it did the same thing but it was idling trying to load a game with only the multi dongle connected and no mod work was done previously
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Do you have a picture of the power supply you bought? There are two models of the twisted quarter power supplies. The normal one with -5v and the one with 3.33 volts, used for the Namco system 23, Sega Naomi or other arcade games that use 3.33 volts. My guess is that you may have bought that version of the power supply as these power supplies have a built in breaker fuse to prevent shorts and damages to your hardware.
 
i got the one with -5 volts. wait does the 2x6 need 3.3 volts? i do have one for my naomi.
 
triforce7770 said:
i got the one with -5 volts. wait does the 2x6 need 3.3 volts? i do have one for my naomi.
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No, the system 246 only uses 12 volts and 5 volts DC. Since you got the recommended power supply, check the fuse and check the fuses on the Namco system 246.
 
I think psu is ok. Noticed when I nudge the vga connector on the pcb side the power kicks off. Kinda weird. And it only now turns off doing so.
 
Could something on the motherboard have shorted? Possibly a fuse or resistor? 5 volts does go out through the vga connector, I believe it’s pin 9.
 
OK now im not getting any video what so ever! lol. Monitor is getting a no video signal. I tried adjusting the ps2 av cable again and no change. if i take out the ps2 av cable out still no change in picture. if i move around the vga connector i get a slighty different picture with slightly wavy raster lines like its trying to sync. it was working perfectly fine a few days ago i havent touch it since than. only thing i changed was the usb for the ide simulator because i wasnt getting past the namco splash screen. Also tried another pcb and that works perfectly.
 
Here a pic of the monitor with no signal
 

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So i tried a couple of things to see if i get video, changed the vga cable and same thing it wont sync or anything. Also got a ps2 composite cable and hook it up to an old crt jvc monitor and same thing no changed even changed the dip to c-sync since i was running composite as well. maybe something on the motherboard thats causing this issue? other pcbs work fine with signal.
 
Composite video cables won’t work with the system. Component video cables will give you a blue screen unless you have a 31khz compatible game, unplug the av cable while it’s on, plug in the component video cable and a picture will come up, but it will all be pink. The PlayStation 2 motherboard has some video circuits removed as they weren’t necessary, the arcade system doesn’t use sync on green like a traditional PlayStation 2.
 
gotcha i do have a set of retrovision component cables and a sony pvm to test it out. will do later this morning. Also thinking my usb is acting funny with the ide simulator. maybe thats reason why im not getting any video also?? got a 8gb im also gonna try later as well.
 
Probably that’s your issue, some games will not boot if the I/O or game files aren’t present. If that happens, usually some sound would come out of the rca jacks. Repeating Wah sounds.
 
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