Installation - SukkoPera/SMSPlusPlus GitHub Wiki

The following installation instructions are are based on the IC BD M4Jr. PAL revision of the Master System II logic board. Hopefully other Master System II boards are not too different, but the original Master System is definitely another story.

  1. Take your console apart, remembering which screw goes where, and remove the logic board.

  2. We're going to work on the back side of the board first. We will need to sever all connections from the controller port to the I/O chip. Use a razor blade and/or a sharp cutter and take your time. Keep cutting until you get to the white layer. Be aware not to touch nearby tracks! Use a multimeter (and the table below) to check that you have really interrupted the electrical connection.

pics/traces_to_be_cut.png

It's a good idea to apply some insulation tape over the cut traces, to make sure that the wires we will be soldering later won't make contact with the traces.

  1. Solder 7 wires, possibly of different colors to the numbered pads above.

  2. Take 7 more wires of the same colors you used before and solder them to the I/O chip (IC4, 315-5237) according to the following table. Note that for a couple of wires you need to add a series resistor. The actual resistor value is not critical, anything in the 1k-10k range will probably do. I used 1k.

    IC4 Pin # Pad Port Pin # Signal Wire Color Inline resistor
    10 1 Up Blue No
    11 2 Down Purple No
    12 3 Left Orange No
    13 4 Right Red No
    14 6 TL (B1) Yellow No
    20 9 TR (B2) Brown Yes
    21 7 TH (Light) Green Yes

  3. In the end you should end up with something similar to the following. All wires should head to the right side of the board (which is the LEFT side for us, since we're working on the back of the board!). I suggest to put some blobs of hot glue here and there to hold things in place, like I did. I know I am no elegant modder. Feel free to do a better job than I did and submit pictures :smile:.

pics/io_chip.png

Note that there is no particular reason why the blue and purple wire are separate from the rest, I only added them later because I'm lazy, but they should all go together.

  1. You will need two more wires to power your modchip, carrying +5V and GND. There are plenty of points on the board to take these from. I chose the two points that you can see in the upper left corner of the above image (Red is +5V and Brown is GND), feel free to do the same.

  2. Work on this side of the board is over, time for a test: temporarily connect wires of the same color, power on your Master System and play a game. The controller should work normally. Now disconnect a wire at a time and check that the corresponding direction/button stops working for every wire you disconnect. If a button keeps working, recheck the traces you cut before.

  3. If you want to be able to reset your console, you will need to disconnect pin 33 of IC4 (315-5237) and lift it away from the SMS board. I actually recommend to just cut it as near as possible to the board using flush cutters, or you can make use of some of the ideas at http://mercatopo-en.blogspot.it/2012/03/add-reset-button-to-your-master-system.html. Once you have lifted it, solder a wire to it. This will be your RESET OUT signal. I recommend to hold the wire in place with some hot glue, to avoid ripping your pin out if you pull the wire by accident.

pics/ic4_ic5.jpg

  1. If you want to be able to change the video mode, you will need to repeat the above with pin 57 of IC5 (315-5246) and solder another wire to it. Check the above image. This will be your VIDEO MODE OUT signal.

  2. If you want to be able to change the video mode from the console as well (and/or to turn the Pause button into a Reset button), you will need to lift the upper two pins of the Pause button from the SMS board and solder a wire to one of them. I would recommend cutting the left leg, which is closer to the shield, and lifting the right one. Actually, I find it easier to desolder the whole Pause button, lift the top legs and resolder the bottom legs. Whatever you do, make sure that the lifted legs do not touch the metal shield, apply some heat shrinking tube or insulation tape. This will be your PAUSE IN signal. Note that if you are using an Arduino Nano, you will need to install a pull-up resistor (1k-10k should be fine) between PAUSE in and 5V!

pics/pause_in_out.jpg

  1. Solder a wire to the bottom leg of R9 as you can see in the above image, or to one of the pads you just removed the Pause button legs from. This will be your PAUSE OUT signal.

  2. All done, you can put the board back into the case. I suggest to cut part of the edge of the bottom metal shield and to straighten it, to allow some space for the wires. Note that the edge of the metal will be sharp, so apply some thick tape on all edges to avoid cutting wires or yourself!

pics/bottom_shield.jpg

  1. Finally connect all wires to your chosen chip and enjoy!