Genesis 3 tear-down and documentation (56K FAIL)

[Basement_Modder]

Just going out on a limb here...
maybe one of the caps is on too long of wires/ is wired in reverse/ got blown. That would be an easy fix.

 

[zeturi]

No, I did not abandon this thread. I resoldered the 7805, and connected it to my lcd.
To my surprise, the lcd went black! I remembered that my genesis used to show a black screen on startup if the cartridge wasn't clean or inserted right. So I'm gonna check the soldering on my game cart , and repair it if I need to. If it works then yay!

EDIT: Oh yeah, in case anyone is wondering, I cut my motherboard down with an ordinary pair of paper scissors. I used a pair of pliers to force the blades of the scissors down. It cuts faster than a dremel, I think, plus I cut pretty straight lines.

 

[robm]

Here's hopin!

I am to be receiving a Genesis motherboard, which I will use for determining if CD/32x compatibility is possible on the G3.

 

[zeturi]

Well, I tried everything, but will wait till tomorrow to test.

I redid my capacitors so they don't even need wire to lay flat. I trimmed my motherboard just a bit more. I also redid my cartridge soldering. I just have to solder on the front half of the cartridge, and see what happens. Just fyi, the dimensions of my motherboard are 10.3 cm x 11.3 cm, and just under a centimeter thick.

The only thing left that I could cut now is where the cartridge used to connect, but I don't think I'm skilled enough to solder to the alternative spots on the board. And I cut my motherboard with scissors, a pair of plyers, and my death-grip. Pics tomorrow as well!

 

[Tibia]

Here's hopin!

I am to be receiving a Genesis motherboard, which I will use for determining if CD/32x compatibility is possible on the G3.

Has that shown up yet? I thought it would have gotten there by now.

 

[robm]

Nah, if you sent it Friday, no deliveries Sunday or today...

It'll be here tomorrow. And thanks again!

 

[robm]

First, let me say I had talked about with Palmertech last week about making this a sticky, as the forum doesn't have a whole lot of those right now. We agreed it has enough information to qualify, so sticky-fied it has been.

If all is in disagreement, I shall de-sticky-fy it.

On a related note, I received the Genesis motherboard, and it seems that there IS a serious possibility for SegaCD and 32x compatibility on the G3. However, it should be noted that it does not look like the project would be for novices - direct soldering of wires to a 208-pin micro is involved.

 

[XCVG]

First, let me say I had talked about with Palmertech last week about making this a sticky, as the forum doesn't have a whole lot of those right now. We agreed it has enough information to qualify, so sticky-fied it has been.

If all is in disagreement, I shall de-sticky-fy it.

On a related note, I received the Genesis motherboard, and it seems that there IS a serious possibility for SegaCD and 32x compatibility on the G3. However, it should be noted that it does not look like the project would be for novices - direct soldering of wires to a 208-pin micro is involved.

Don't dismiss the novices so fast- one of them did an RCP relocation ON HIS FIRST TRY!

I think.

 

[robm]

You know, I think I remember hearing something about that. I think that would be one of those "portable" novices who weren't a novice in regards to soldering. Either that, or the guy found his calling on his first try

I hate fine-pitch soldering by hand with the burning passion of a thousand suns.

 

[XCVG]

You may or may not find info on this site useful:

http://devster.monkeeh.com/segapage.html

EDIT: Perhaps this will be of help:

http://www.assemblergames.com/forums/sh ... p?p=366146

Man that Nomad board is tiny!

 

[robm]

Fantastic links, thanks!

 

[zeturi]

Guess what?

I haz it working!

I'll post pics in a second.

EDIT: Here arez the epic pic! (Ignore the piles of crap around it.)

So, in other words, I cut most of what Robm did in his diagram, just did't rewire were the cartridge connects to the motherboard.

Thanks a million, Robm!

 

[robm]

Good job!

Glad to see someone benefited.

 

[zeturi]

I only cut the grounds at first, but your diagram showed me a little more places that could be trimmed.
As I mentioned, my cut board is 10.3x11.3 cm, but you can get it to about 9.5x10.3 if you rewire where the cartridge connects. Either way, this motherboard would be excellent for a portable. Expect a genesis portable sometime in the future!

 

[Bibin]

This looks like it is actually the very first GOAC. I don't see the M68K nor the Z80. The entire chipset looks to be inside the large square package, save for the video encoder and the RAM banks (maybe a few other tiny things too)

 

[Bibin]

First, let me say I had talked about with Palmertech last week about making this a sticky, as the forum doesn't have a whole lot of those right now. We agreed it has enough information to qualify, so sticky-fied it has been.

If all is in disagreement, I shall de-sticky-fy it.

On a related note, I received the Genesis motherboard, and it seems that there IS a serious possibility for SegaCD and 32x compatibility on the G3. However, it should be noted that it does not look like the project would be for novices - direct soldering of wires to a 208-pin micro is involved.

Hey now, we already knew it could do 32x and CD.

 

[zeturi]

A great goac, then. It has good compatibility, from what I hear.

 

[zeturi]

I would like to mention that if you are willing to relocate those black resistors near the controller ports, you should be able to shave off about another 7 mm off the board. I will attempt this right away, otherwise my genny ain't gonna fit.

EDIT: Yep, worked just fine. You can completely bypass those black resistors (or caps? never seen anything like these) and just plug in from there. I have been able to omit the 100uf capacitor that was in between the these two resistors. My Genny still runs!

 

[zeturi]

I'd like to make a bit of an update. I have taken some good pictures of a genesis 3, with only two modifications: The reset tact switch is gone and there is some ink on the power switch. Otherwise, I got some nice high res pics now.

Top:

and bottom:

 

[Mako321]

blurry first picture is blurry.