Capcom I/O Upgrade to Power Up Dimm Boards?!

[Derick2k]

Has anyone tried to mod the capcom i/o to supply the necessary power for the naomi, netdimm, etc?

I know it has a mini DC to DC converter board soldered to it. Most likely used as a stepdown to supply 3.3V, maybe that circuit could be replaced/improved to provide the necessary power to boot up the naomi with all needed accessories??


Found a pic of a capcom I/O pcb and highlighted the section I am speaking of:

 

[RealMFnG]

Out of box thinking. Me likes. More amps channeling through the Capcom I/O please!

 

[Derick2k]

Ok, for those that requested more info on this upgrade to the capcom io. THis is not a full write up or anything of the sort. I am short on time as I am in the middle of transition to a new job among other things at the moment.

But all that is needed to be done is to replace the oem dc to dc converter as pictured/highlighted on the first post.

You will need a 5vdc to 3.3vdc stepdown or "buck" converter as they are referred.

I have tried various types with different ratings some adjustable and some fixed, some might need an additional cap or resistor here or there to dial them in. You need to read their datasheet and understand what you are doing.


I have successfully used these types (I dont mean go and get this same one as this one would push out about 12A you should only need as a max 5-6A) This one is voltage adjustable which you would want, and there are some that are current adjustable as well which is also good. This way you can adjust your 3.3 voltage and current as needed.

http://www.ebay.com/itm/DC-DC-12A-A...v-Step-Down-/191842317007?hash=item2caab172cf



I have also used these types with mini heatsinks, although I can probably use them without or just add a fan if you are worried about heat dissipation. Based on their specs, these seemed to have been made for the task we need them for. These are much better quality than the above I believe , but do require some tweeking in most cases to get your 3.3volts dialed in as the way to trim the voltage up or down is done via resistors, you could use a trim pot for this purpose as well I guess to make them adjustable, but I have found that they mostly work out of the box.

http://www.ebay.com/itm/262754297285?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT


Again read the datasheets for these converters.

This is not meant to be a full step-by-step guide, its only meant to guide you in the direction what to look for and do. I like people to learn the what it is and why it works in what they are doing.

Hope this helps some to do this mod. I would like to see the results others get with these and/or other converters, please post about it. Could be that there are some out there that are better than these, I dont know.

 

[twistedsymphony]

I saw AMB advertising a Capcom io modified for enough output on the 3.3v line to support a DIMM board... anyone know what it is he's doing for that?

 

[Derick2k]

I saw AMB advertising a Capcom io modified for enough output on the 3.3v line to support a DIMM board... anyone know what it is he's doing for that?

I am sure its the same thing I did as it's the only logical/simpler thing to do. The dimm board and naomi as far I as measured on my units only draw on the high end about 4.2-4.5amps on the 3.3v line so the above dc-to-dc converters or similar output enough to power these up.

If anyone has one of these upgraded io from AMB I would love to see what he did as well, so please post some pics.

 

[penrhos]

I found a nice 5A adjustable +/- 0.2V but it also has a current limiter pot - do I just turn it up full?

 

[Derick2k]

I found a nice 5A adjustable +/- 0.2V but it also has a current limiter pot - do I just turn it up full?

It should be ok, but I hate to run things at their maximums. But please do test to see how it works for you. Measure the current draw with your setup if you can, I would love to get some numbers on what the naomis and dimms are drawing.

 

[Derick2k]

Upgrading another io, running tests on a new sip packaged dc-to-dc converter.

Solid output on the 3.3v line, stayed between 3.31-3.32v even while I adjusted the 5v line. Runs very cool thus far, will put it through a torture test this weekend to see how it handles.

Not the cleanest install, but all works as it should.

 

[werejag]

if i can swing for one of those i/os one day ill get you to do it for me

 

[chinitosoccer]

Would this mod work with a GDrom?? I would like to reduce the cabling when using the naomi+capcom IO with my supergun.

 

[opt2not]

Solid output on the 3.3v line, stayed between 3.31-3.32v even while I adjusted the 5v line. Runs very cool thus far, will put it through a torture test this weekend to see how it handles.

How did this test go? I'm interested in doing this mod too.

 

[XeD]

I use a picopsu and no problem here

 

[Derick2k]

Solid output on the 3.3v line, stayed between 3.31-3.32v even while I adjusted the 5v line. Runs very cool thus far, will put it through a torture test this weekend to see how it handles.

How did this test go? I'm interested in doing this mod too.

It worked out fine, but a custom built dc to dc converter to replace the stock one would be better suited than off the shelf parts. I used the bigger converters with heatsinks with better success, tight fit.