Bibin's SEGA thingy (unnamed as of yet)

[Bibin]

Sorry I posted this here; nobody ever looks at the sega section though.

I found an old working sega nomad with a busted screen. Meanwhile, I'm having trouble fitting my sega genesis Model 1 in with my many other consoles, as it is not stackable unlike the NES, Wii, and front-slot atari bibin has set up in the living room. This poor nomad was just screaming to me "Tear me apart! Make me into a slim sega genesis! You already have a working nomad! Bring me life! LIFE!"

Of course, first I'd have to take it apart.

Let's get onto that:

The first four screws were easy to get off. However, the last one, located on the bottom-centre... It was one of those blasted NINTENDO SCREWS! I thought "SCREW this!" (CLEVER EH? EH?) and just ripped that sucker apart. I broke a screw post. Boo hoo; I frankly don't care.

Now that this thing is apart, I'm stuck. It has a small board on the rear-nomad-piece containing the cart slot, the second controller port, and clearly the genesis itself. It is labled with "PC BD VENUS MAIN" Which clearly indicates that this is the mainboard of the nomad, codename "venus".

On the second side, the one containing the screen, A/V output, DC in, power switch, buttons, and speaker, there was a much larger board. This is the daughterboard, despite being larger. The two are connected by a 30 pin ribbon cable, large enough to be easily soldered to and extended if need be.

Now, since that smaller board is clearly the bulk of the genesis if not all of it, it should function on it's own. It also contains its' own non-charging battery terminals, which are just my way of saying "secondary DC-in". I've wired 9 volts to them before on my *other* nomad and it works fine.

I would assume that this 30-pin connector contains the extra DC in, the RGB signal, the audio, and the controller buttons.

Let's see here:

RGB: 4 pins (R, G, B, sync) or 3 pins (R, G+sync, B)
Composite: 1
Some power: 1
Controller: 12, assuming each button gets it's own, counting mode
Audio: 2 (L and R)
Power Switch: 1
Ground: 1
Probably an extra ground for good measure: 1

Hmm, that's just twenty three. Regardless, this ribbon will certainly contain an RGB signal, and the controller. Those are the things I need from it.

Why an RGB signal? Well, the sega nomad LCD was an analog RGB screen. The little AV plug on the top of the nomad outputs RGB and composite, a benheck hacker's saviour. The composite is generated on the daughterboard, I think.

As I need this to output composite, I'll likely have RGB and composite pins on the back, as I'll want to some day have it use RGB for when we get a fancy TV.

If I need to, I will keep that nasty large daughterboard and remove the LCD, inverter, backlight, and speaker, leaving only what's necessary. Then I'll need to wire up a controller port for player 1, as the nomad previously relied on using built in buttons.

I aim for this to be about the size of a closed laptop, about 1" thick.

So yeah, I need help from here. Do I need to use that daughterboard, or is there a way I can just use the mainboard?

[bicostp]

You might as well keep everything together; the Nomad's pretty small as it is.

Sorry I posted this here; nobody ever looks at the sega section though.

<a href="http://forums.benheck.com/viewtopic.php ... 263015">We don't care.</a> Posts belong where they belong.

Moving...

[Bibin]

If I keep the nomad as it is, though, it'll be really hard to connect a controller, have proper AV out from the back, have a front-inserting cartridge slot, and be something that will stack nicely underneath a NES and on top of a front-loading Atari.

[nubie]

Hmm, ever consider a Radica?

Just out of curiosity, I realize it is a bit hard to attach the game connector, but it seems to be really compatible after a quick hack to disable the onboard bank switching:

http://forums.benheck.com/viewtopic.php?t=17720

I am amazed that you found a working Nomad, cool. As far as stacking goes, maybe a sheet of thin board with some standoffs could be used as a base for the Nintendo to sit on, then hang the Nomad under it with cable ties or screws or glue etc, with a couple controller extenders on either side, either solder your own, remove and extend the existing ports (I don't like this one, dangerous), or buy these ($2 each, not affiliated, just googled 1ft DB9 extender) http://www.yourcablehookup.com/cables-t ... -8745.html

Then put the end with the cartridge sticking toward the room. If the video output is on that side, just carefully re-wire it to some good quality connectors and put it on the rear of the board, maybe breakout the S-Video or the A/V if that is what you use. Some of the docs here may help with the video pinout (might not too, I don't know, did the nomad use the Saturn/Genesis III video port? Might check that page.): http://emu-docs.org/?page=Genesis

[c_mon]

So yeah, I need help from here. Do I need to use that daughterboard, or is there a way I can just use the mainboard?

This project was done by me recently. Check it; you'll find some info...




http://forums.benheck.com/viewtopic.php?t=21428

[Bibin]

Well, it looks like I'll be using the daughterboard; however, I can't see from your project where you got controller inputs working; did you just solder individual buttons to the original pads?

[c_mon]

I soldered the controller wires to Nomad's mobo. Nomad has its own built-in controller so I used its traces.

[ttsgeb]

I would think if you were trying to mod it to have 2 controller ports, you would want to find the chip for the built in controller, and connect the port to bypass that chip. That way you don't end up having to build a custom controller for it.

I may just try to make a pin out for that 30 pin cable at school tomorrow, I do spend 3 hours waiting for my ride, most of the time either playing or disassembling my nomad...

honestly though, for making the nomad a stationary console, I don't see why you would be so worried about the daughterboard, if you lay them both flat, you can get and incredibly thin, front loading system. The highest part on the board is about half an inch high.

Also, since you brought up the battery terminals, which is positive and which is negative?... I've been meaning to build a battery pack and don't have this information.

[Bibin]

I believe the top is positive.

[ttsgeb]

ok, I'll trust you on that one, but if I fry it, I'm gonna blame you... and then get a bunch of extra pieces.

well, here's what I came up with at school using a magnifying glass on the daughterboard:

http://img99.imageshack.us/img99/5017/pinoutjt5.png

It's quite large being directly from my scanner, and I wouldn't trust it to greatly. I'll have to compare it to my Model 1 schematics and see if I can figure out anything more helpful.

[Bibin]

I tried backwards and forwards to try the hard way; didn't fry anything, just don't test it for extended periods of time.