Powering GDROM + Naomi 2 + Capcom I/O in Astro

OldFoo · Post by **OldFoo** » Sun Aug 02, 2009 9:34 pm

Ah, if its just to power the GD-ROM drive and not the motherboard and dimm (I didn't realise that before!), I guess it would work, though I still think you should drive the entire Naomi setup off a single power supply so there are no grounding issues.

OldFoo · Post by **OldFoo** » Sun Aug 02, 2009 9:42 pm

It's ok to use multiple power supplies as long as you don't attempt to use more than one psu on any single device.

OldFoo · Post by **OldFoo** » Sun Aug 02, 2009 11:39 pm

So the GD-ROM and DIMM being powered by separate PSUs wouldn't be a problem? I would have thought there might be a possibility of a potential difference being created over the ground lines in the SCSI cable due to the fact that the ground connection isn't going to be always the same on both PSUs.

OldFoo · Post by **OldFoo** » Mon Aug 03, 2009 1:11 am

The SCSI grounds are for the return of the digital signals, not power. They are isolated from the power supply.

OldFoo · Post by **OldFoo** » Mon Aug 03, 2009 2:38 am

Just to be clear, I can simply splice the new PSU into the power lines leading to the Astro PSU, right?

OldFoo · Post by **OldFoo** » Mon Aug 03, 2009 3:59 am

Are you sure it is not possible to use DC OUT 2 on the Astro PSU to power the GDROM drive alone? Granted, I don't really know what I'm doing, but I poked around with my multimeter and it appears it may have a +5 and a +12 coming out of it.

Using this for a diagram of the DC OUT 2 plug, as you look into the cab from the front -

back

1 2 3

4 5 6

front

when I put my negative multimeter probe in holes 4, 5, and 6 and poked 1, 2, and 3 with my positive probe, I got these readings:

1 - 12.xxv

2 - 5.23v

3 - 5.23v

4 - 0v

5 - 0v

6 - 0v

Looks like 4-6 are grounds. So why can't this work? Wasn't powering the drive AND the mobo + dimm at the same time through the jamma harness the big drawback?

OldFoo · Post by **OldFoo** » Mon Aug 03, 2009 2:35 pm

Is it possible? Yes, if your power supply has enough output to support the entire game system. If your cab has the usual standard 15AMP psu, then it will not work. If you can't tell how much output is available, splicing the wires won't hurt as you will find out soon if it works or not.

OldFoo · Post by **OldFoo** » Mon Aug 10, 2009 5:37 pm

i had issues with powering gd-rom off capcom i/o way i got around it was to use a naomi sun psu to power the mobo and the gd rom setup just i left the capcom power supply cable off and then pluged it in to usb vga etc and it work great.

the dimm wouldent even power up under capcom alone.