Genesis 3

The Genesis 3 has had a lot of negative attention over the years, but I think it’s a great console with a ton of potential!

Overview:

Let’s get right to the shortcomings – While all Genesis 3’s do output RGB video, audio is mono-only and 32x, SMS, Game Genie, Virtua Racing and Sega CD will not work.  Luckily, A/V output can be near-flawless on every model and functionality can be restored to different levels, depending on revision.

 

RGB Output

There was an internet myth that some Genesis 3’s didn’t output RGB.  This has been disproven time and time again;  As long as you use a cable that can fit through the deep A/V port hole, RGB will work.  On top of that, the video output is actually quite good!  Stock video looks better than most other Genesis revisions and simply lifting the subcarrier pin (as described in the Genesis RGB bypass section) will remove almost all interference at the cost of disabling composite video.

For perfectionists, performing an RGB bypass with all signals isolated (pins lifted, etc) will result in a near-perfect analog output!

 

Audio Output

The Genesis 3 only outputs mono audio, making it a poor choice for use without modification.  Luckily, there are a few excellent choices for audio bypass:

– The Mega Amp is a great solution that will allow for excellent quality audio that’s on-par with original Genesis audio.  I suggest using this if you plan on keeping composite video and using the stock RGB output.

– The Triple Bypass is both an audio and video bypass board and in my opinion, the perfect choice for the Genesis 3:  You get near-perfect audio and video output, installation can be made a bit easier by removing the Sony CXA1645 and soldering those points and the only thing lost is composite video support.

 

Motherboard Revisions

There are two board revisions of the Genesis 3, the VA1 and VA2.  You can determine board revision by opening the cartridge slots and matching the board traces.  The picture below might help and I’ll have better pics of the cartridge port differences up soon.

Once the console is open, it’s very easy to spot which revision based on the orientation of the main Sega GOAC chips:  The VA1’s have a Sega 315-5960 GOAC chip oriented the same as the cartridge port and the VA2’s have a Sega 315-6123 GOAC chip pointing at the cartridge port.

 

 

Game & Accessory Functionality

Luckily, Genesis 3’s can have much of the functionality of an original Genesis restored by connecting some pins on the GOAC that are missing connections to the cartridge port (see diagram below).  Neither can connect to a Sega CD, but here’s what you can restore on each:

Genesis 3 VA1:
The VA1 can have 32x, Virtua Racing, Game Genie and SMS (without FM audio) support restored.  Just run wires from the following pins on the cartridge port to the Sega 315-5960 GOAC:

B1  ->  Audio circuit*
B3  ->  Audio circuit*
B12  ->  Pin 24
B13 ->  Pin 25
B14 ->  Pin 26
B15 ->  Pin 152
B19 ->  Pin 151
B21 ->  Pin 158
B30 ->  Pin 43
B32 ->  Pin 42

INSTALL PICTURES COMING SOON!!!

*Connect the audio circuit to the corresponding location on either the Mega Amp, Triple Bypass or Onboard Audio using 75ohm pull-down resistors.

Genesis 3 VA2:
Unfortunately, the VA2’s can only have Virtua Racing and Game Genie functionality restored, resulting in no expanded functionality past the Genesis library.  If you’re using a Mega SD, you can restore Sega CD audio though, by connecting B1 and B3 as explained above.

– First add a short jumper wire between cartridge pins B26 and B11.

– Then run wires from the following pin B19 on the cartridge port to pin 154 on the Sega 315-6123 GOAC chip:

Here’s a picture showing a simple way to restore this functionality, with easy-to-solder locations on the bottom of the board.  I haven’t tested this personally yet, but this was found and verified by Frank Strasser:

LeonK took a second look at the VA2 and verified the research Ace and others already confirmed:

I suspect DRAM integrated on VA2 and 32X support removed, as“:
-VA2 uses a 208 pin VDP
-VA1 uses a 160 pin VDP
-VA1 has IC5 (64K DRAM) and not VA2

 

This information was made available by the awesome people on the Sega-16 forums, who traced the pinouts for both models of the Genesis 3!

 

Cartridge Pinout

 

Triple Bypass / Mega Amp / RGB Bypass installation pics

A full installation guide is coming soon!  For now, here’s pics of a tested and working Sega Triple Bypass installation that advanced users can reference as a guide:


 

For more information on Genesis / Mega Drive consoles, head back to the main Sega Genesis page!