Jamma Genesis

[Kid Panda]

Most games work with the Genny controllers but There is a mod that will need to be done to the controllers that allow for use on the SMS for a handful of games. It can be enabled and disabled by using a switch.

Those games that need the OG control suck anyway

 

[Lemony Vengeance]

Agreed, but its about compatibility, right?

BACK ON TOPIC

For those that didn't follow Coryoon!'s thread, if you're having color issues (colors , not brightness too dark even when tapped from the correct spot) you need to add 75 ohm resistor, then 470 uf capacitors (with the - toward the jamma edge) to the R, G, and B lines:

Jamma edge------ (-)470uf(+)-----75 ohm------ color location

 

[Nerdygrrl]

Thanks guys much appreciated. Hopefully I can get the Super 29 sorted out and then I can work on picking up a Genny. Must not get ahead of myself.

 

[Lemony Vengeance]

For those that don't know.. The Sega CD can accept up to 18v of power. this means you can power it from the edge with 12v and it'll be just fine! And to prove it, here's 68k:

 

[Lemony Vengeance]

Recently JAMMA-fied a Genesis 3:

Here's where you need to pull RGB and sync:

(Purple is on the red line)

The caps and resistors on the RGB lines aren't needed, Nor is the Sync cleaner. I suspect this is the same as the Genny 2 since it also uses the CXA1645M in some revisions. The colors would be tapped in the same place.

 

[bustedstr8]

Frikken cool Lem. I never realized how small the Gen3 pcb was. Did you think of modding the case to hold the Jamma edge?

 

[Lemony Vengeance]

Frikken cool Lem. I never realized how small the Gen3 pcb was. Did you think of modding the case to hold the Jamma edge?

I would have, had this been sent to me with the shell (its a commission). I'm going to get a project box and wire a switch with an LED in it for power on. I'll also probably add L/R stereo out because i like to tinker.

Besides, I kinda like how the edge was mounted. Worked out well. These things are tiny, so even I I did have the shell, I don't know if it could have been mounted to my satisfaction.

 

[Yodd]

Very nice work Lem!

 

[Neo Ash]

Nice! That's some super clean work Lem.

 

[Lemony Vengeance]

Thanks! I'm going to cut the JAMMA PCB so it's flush against the Genny PCB.

This thing was so easy to mod, that unless people specifically want a model one, I'm going to go with model 3's from here on out. RGB video is pulled before it hits the encoder, so it doesn't matter what's in there. As for sound, I believe the model 3's sound is decent.. I may be wrong.

 

[lantus360]

hows the picture? I did the same thing with a Genny 2 (tapped the signal before the encoder) and the colors seemed to 'bleed' a little.

 

[codecrank]

very cool lem ! your works just keeps getting better and better

hows the picture? I did the same thing with a Genny 2 (tapped the signal before the encoder) and the colors seemed to 'bleed' a little.

which genny 2 did you use ? so many models...

 

[Atro]

very cool lem ! your works just keeps getting better and better



which genny 2 did you use ? so many models...

I believe he said Genny 3.
Awesome job Lem. I have to get some fingerboards like those.
I bought some crappy ones back then.

 

[GohanX]

As for sound, I believe the model 3's sound is decent.. I may be wrong.

I've never had one, but supposedly the Model 3 has excellent sound, but stock it's mono. That has no relevance to this since you can leave it mono for cabs or tap L and R stereo internally anyway.

 

[Lemony Vengeance]

I'm to put it in an enclosure, but finding something that's 6 in x 5 in x 1.5 in is proving to be tough. may have to make it 2 in tall.

 

[codecrank]

I believe he said Genny 3.
Awesome job Lem. I have to get some fingerboards like those.
I bought some crappy ones back then.

oops I meant to quote lantus about his genny 2 purchase

 

[kraquepype]

That model 3 jammafied looks very clean... Great work. I want to give this a shot soon so I can play SoR in my cabinet!

 

[Lemony Vengeance]

Shadows made an integrated genesis on a Jamma edge PCB and was nice enough to send me one, but it was picky about the 74157 ICs I used.

What I'd REALLY like to do is to design a PCB that sits around the underside of the controller port pins that will run the 9 signals through this circuit:

http://gamesx.com/wiki/doku.php?id=controls:megadrive_genesis_controller_3

and break them out to the individual outputs. As for overhead, I'd go with SMD as it doesn't poke through to the other side. TI makes the SN74HCT157D.. this would wok just as well, correct?

It would have the Sync separation and Color boosting circuits built in as well (all SMD, of course)

It's pie in the sky, of course. I have no experience with PCB design at all. :/

I need to do some more testing of the J-Gen3 between my NAC and Blast to see if the Color boosting caps/resistors are still needed. At first glance I deemed them unnecessary, but after playing with some games I'm starting to think maybe(?). I'll let you know.

 

[MuppeT]

dbl post

 

[MuppeT]

I got inspired and decided to try and jamma a geny 3. Bought one, came home , opened it and it is different from the one on the pictures from lemony
Can someone help me from where should I tap to get the R G B and sync ? Can I get them from the Din socket?
Here is a pic of the board my geny 3 got :

 

[Lemony Vengeance]

I got inspired and decided to try and jamma a geny 3. Bought one, came home , opened it and it is different from the one on the pictures from lemony
Can someone help me from where should I tap to get the R G B and sync ? Can I get them from the Din socket?
Here is a pic of the board my geny 3 got :

View attachment 22774

Hmmm lemme dig in.

 

[MidnightMonkey]

You should be able to pull everything right from the CXA1645. All gennys use the same chip IIRC. I don't remember if you need to build an amp for the signals tho.

 

[Lemony Vengeance]

You should be able to pull everything right from the CXA1645. All gennys use the same chip IIRC. I don't remember if you need to build an amp for the signals tho.

No amp or color boosting circuit is needed if you pull from where I pulled the colors from. The location in the circuit is the same, but the location on the board is different.

I've had the flu for the past week or this would have been answered sooner.. I just caught the post today. I'll plpoint out the color points later on.

 

[cr8zykuban0]

damn, genesis running on a cab? that is awesome. the picture quality looks beautiful

 

[Lemony Vengeance]

I got inspired and decided to try and jamma a geny 3. Bought one, came home , opened it and it is different from the one on the pictures from lemony
Can someone help me from where should I tap to get the R G B and sync ? Can I get them from the Din socket?
Here is a pic of the board my geny 3 got :

View attachment 22774

Heres where I think you can pull the colors and sync

The colors I'm pretty sure about, but the Sync may need to be traced back behind that cap. Give it a shot and let me know