Portable Game Systems Explained (NES)

In this instructable I will be explaining step by step, in as much detail I can provide, on how to create a functional portable game system. Most of these steps carry over between most systems of the older generations with minor differences, although as you move onto newer and newer systems these explanations will become less and less relevant. This is because newer systems are more complex, although the following steps still apply. You will just need to put in extra work to research where specific functions are located on the console such as video out, audio out, power in, required voltage for the system, etc.

This instructable will be working with the Nintendo Entertainment System, although these steps can be applied to other systems around the same generation like the Atari, Nintendo 64, and  Sega for the most part. There are a few differences between them but the basic theory still applies between consoles.

Some of the mandatory tools for this instructable are:

-Multimeter
-Basic hand tools (screw drivers, files, pliers)
-Dremel
-Soldering Iron
-Heat Gun
-Basic electrical/schematic knowledge

There are also parts which need to be purchased ranging from protoboard, misc. resistors, capacitors, momentary switches, and a lcd screen. When these extra parts are required I will bold them in a list near the top of the step.

This is not an easy task and you can expect to put at least a week or more into this project depending on dedication. The portable NES took me a little over 2 weeks working on it in my spare time.

If I stated anything wrong or if you need a better explanations just leave a comment and I will attempt to clarify it to the best of my abilities.

That's it for the intro, lets get started!

Parts List:

-3.5 - 5 inch composite lcd screen (Can fetch these off ebay for cheap. Search "Rear view car camera LCD", I used a 3.5 inch screen)
-7.2 volt NiCD or NiMH battery (Can also get these off ebay, I went to a local hobby store and got ripped off unfortunately)

Once you verified you have a working console, because frankly  you can't work with a broken console, it is time to disassemble the console and find your working voltages.

In the case of the NES on the bottom side of the console there are 5 or 6 screws which conjoin the two shells of the body together. Once these are taken out you can flip it back over and remove the top half of the consoles shell. This will reveal a bunch of sheet metal shielding in most cases along with heat sinks in some consoles such as the N64.

From here it is time to tear down the console until you can successfully remove the entire motherboard from the shell. There are 6 or 7 screws holding down the top metal shielding which once taken off reveals the spring loaded cartridge loader. After that you will need to unscrew the start/reset switch, player controller ports as well as the motherboard itself. By now everything should be pretty loose and ready to be pulled out. If there is binding around any part of the console take a look around carefully before you attempt to pry it out. Most of the time you will simply forget to unscrew a hidden screw. Once you successfully extract everything from the lower half of the shell, remove the spring loaded cartridge holder.

It is time to figure out the working voltages of the console and LCD screen (well you don't have to if you're working with the NES because I am going to tell you them). Plug the console into it's wallwart power source and turn on the console. You are now going to take your multimeter and find the power rails coming after the regulator and negative points on the board. For the NES the entire outer silver strip is a giant grounding plain. In the case of the NES if you locate the RF box which is the oddly out of place silver box you plug your power adapter into you can find a power point. If you flip the motherboard over you can find it being the third solder point from the left (middle solder point).  Alternatively if you skip ahead to the next step you will see a picture with the voltage regular labeled, and you can take your readings off that. If you measure from this point to the grounding plain you will notice the console works off 5v DC, which is funny because the wallwart power supply actually supplies, if I recall, 9 volt AC but that is another story.

After this you need to do the same thing for your LCD screen, but the process is a bit different. You are going to have to follow your power wire from its connector on the PCB, along its traces, until you reach the voltage regulator. If you google the 7805 regulator datasheet you will find a general shape reference. The one in my LCD looked like the 7805, but much smaller. From there you are going to find its output voltage by either googling its datasheet if you can read its label or by using your volt meter and following the previous steps of finding a ground plain and output pin on the regulator. Most of the time the third pin will be the output and the middle pin will be ground. My screen was also running off of 5v DC.

Knowing these you can now figure out your power source for your portable. I normally add 2 or 3 volts above the voltage required by the systems. This is just a general rule of thumb for most regulators, but if you purchase a newer and better regulator you can even go as low as 1.5 volts. In this case both the LCD and the console output 5v DC so adding 2 volts and finding the closest battery that fit resulted in a 7.2v battery. This is not technically a correct way to judge how much input voltage you need to use, but for the most part it hasn't failed me so far for any of my projects. Of course if you are working with newer generations of consoles this rule of thumb may or may not work because newer consoles draw allot of amps. If i recall the xbox360 uses a 12v 12 amp rail and another 5v rail, so not only would you have a tough time trying to find suitable batteries, you would have to find a suitable voltage regulator for both voltages that wont blow up when they system demands 12 amps.

After everything is taken out and calculated, if you want to, you can hook up the console to a power source and a TV to make sure it still works. You may also want to do this periodically in the later steps as well to verify you did not break anything. In the example picture I am using my knife to apply tension to the cartridge. You may have to experiment at this point to find what works because to much tension or not enough will cause the system to continuously reset or power on with a blank screen. I am using a 3.5 inch LCD composite screen and a NiMH battery I bought from ebay wired to the console with some test wires and connectors I made out of spare parts.

Parts List:

*Optional* (These are not needed unless you are picky like I am)
-1uf capacitor
-100uf capacitor
-2.2uf capacitor

-Card edge connector 72 pin 0.1" pitch (A31721-ND)

It is now time to start destroying the motherboard and rebuilding it to make it smaller and thinner. For most consoles you can simply fold and bend over capacitors and resistors to make it slightly thinner, but in some cases like the NES you must resort to physical destruction of the motherboard and components.

**Optional** (This not needed unless you are picky like I am)
The first thing noticed was the blue capacitors that were standing really upright and tall. I took note of their stats and bought new capacitors of the the same stats. You can then begin to desolder the capacitors rocking them back and forth until they come out while heating them with a soldering iron on the back side. After you can take the matching capacitors that you bought and bend the legs 90 degrees and insert them so the capacitor is now laying on its side. Do this will all three capacitors and you will reduce the height of your motherboard by a bit.

Next it is time to physically destroy part of the NES for added size reduction. There is a expansion port which was hardly ever used with the original system and I knew I would never use it in a portable so I proceeded to take it out. Now I couldn't figure out a real way to remove it so I just took a pair of pliers and removed the metal shielding and proceeded to break the plastic. From there you can just wiggle the left over pins back and forth until the snap off resulting in a clean area. Take care not to damage any of the traces on the motherboard or any of the surrounding components.

The next thing that stood out was the original RF box for the console that regulated incoming power, amplified video output, and managed the audio output. The thing was just way to big and was awkwardly placed in the corner of the console so I decided to remove it. This was not a easy thing to remove so make sure you take your time. There are also parts you can salvage to use with other projects as well as one specific part you need to salvage for this one (the 7805 voltage regulator which can be seen on the side of the RF box). As with the expansion port I took pliers and destructively removed it by desoldering and bending away the metal shielding, and snapping the PCB board inside it to pieces to help get it out. Once the PCB is out you can just bend and snap most of the shielding away, although you may need to use the soldering iron to get some of it off of the motherboard, as well as to remove the thick pins that go into the motherboard itself. Take care to really heat up the pins while you pull them out. I made the mistake of ripping them out and they damaged the traces and pads. If this happens though do not worry, you can simply follow the traces upstream and solder any connections to the first component on the trace. Once you are finished If wanted you can desolder the capacitors on the broken RF box PCB for use with future projects as well as this one. Although make sure you keep the regulator from the RF box (the three legged black square on the side of the box) because you will be needing this to reconstruct the RF box in a smaller form factor.

Not pictured is the removal of the power/reset plug (blue) on the right hand side of the board. Since we will be putting an inline SPST switch before the regulator we do not need this to power on the console. I used my pliers again and destructively broke the plastic and desoldered the pins. As a side note, if you want to wire a LED that shows the systems status (reset blink or solid running) you would solder a LED into the top pin which is positive, and the third pin down which is negative.

It is also a good idea to remove the player 1 and 2 controller ports, but we will leave that alone until we get our controllers working. it is much easier to test the controllers when you can easily plug in and out of the system.

Also not pictured is the removal of the cartridge slot which was replaced with a 72pin 0.1 inch pitch card edge connector. This can be bought from digikey and mouser online for pretty cheap (product number for digikey is A31721-ND http://www.digikey.com/product-detail/en/5530843-8/A31721-ND/770547). Simply slide the cartridge connector off and line the new one up and apply solder. Try not to bridge the pads and make sure to check to make sure they are all separated with a multimeter test. I went as far as taking a screwdriver or a razor and running through between the pads a few times just to make sure nothing was bridged. My original plan was to use IDE cable to relocate the connector, but I was getting weird artifacts in the video signal in the games, which was resolved when I soldered directly to the motherboard.

Another Way to downsize the portable is it cut off the ground plains around the outside of the motherboard. Be cautious though, specifically newer systems may have a multi layered PCB which means there are traces on the top, bottom, and middle of the PCB and if you unknowingly cut into them thinking it's only a ground plain you are going to have a bad time. Although with that said, the NES is okay in terms of cutting off most of the ground plain. Just make sure to leave a little bit instead of cutting it off entirely.

Parts List:

**Video Amp**
-2N4401 transistor
-33ohm resistor
-330 ohm resistor

**Voltage Regulator**
-7805 regulator
-2x capacitors (I used two I salvaged from the RF board 470uf and 100uf)

**Audio Amp**
-LM386 or NTE823
-2x 100uf capacitors
-0.047uf ceramic capacitor
-10uf capacitor
-10ohm resistor
-1k potentiometer
-Speaker


In some consoles, specifically the NES, you may need to reconstruct various amplifiers and voltage regulators as you may have destroyed them in previous steps to cut down in size. For the most part the design of these parts are cross compatible as long as you switch out the right parts for your system. For example you are not going to be using a 5v 7805 regulator for a system that needs 12v like the Xbox360.

First we are going to construct the video amplifier which is based of the 2N4401 transistor. This is a really simple circuit and shouldn't need that much explaining. Essentially you have video input and 5 volt input going into the transistor, and then you have your video out into two resistors. One resistor goes to your video output device, the LCD, and the other resistor goes to ground. As you can see the circuit is really small (the size of a penny), and is easy to mount in the device.

You can also notice that I completely destroyed the pads leading to the traces where the RF box used to be. To fix this I simply followed the traces upwards and soldered into the first component I saw. The pin out for the pads from left to right are Video out, Audio Out, 5v In, and I forgot the sequence for the last two, but they are used for the power/reset switch which we will not use.

The next circuit is the voltage regulator. Since we destroyed the original RF box we are going to need a way to turn our input voltage of 7.2 from our battery into an output voltage of 5v for both our console and LCD screen. This is where the salvaged 7805 regulator comes into play. Basically the construction of this device is simple, you will just have to figure out a layout that works for you based from the schematic. I used the 470uf capacitor as a input buffer, and the 100uf capacitor as a output buffer to smooth out the current from the battery and regulator. The input buffer is not really necessary because the current from a battery is normally pretty clean, but a general rule of thumb is to filter the input and output of a regulator. In my first version of this regulator I used the 2200uf capacitor from the RF board but later realized this was not needed. The reason it was in the console in the first place was because the wallwart output an incredibly noisy AC current and it was used as a buffer to reduce the ripples in the current. Also in version two with the smaller capacitors, I snagged the heat sink off the original RF box and trimmed it down and bolted it to the regulator to expel excess heat.

I noticed that the output volume of the console was really weak and this wouldn't fit into my plans of a controllable speaker. I based the audio amplifier of the NTE823 chip which is the same as the LM386. I coupled this with a 1k potentiometer and a small speaker and it worked surprisingly well. The out of place 10uf capacitor is a modification stated in the datasheet which adjusts the amps gain when certain pins are bridged (please review the datasheet, if i recall it was pin 1 and 8). You can also put a resistor inline with the capacitor to control how much gain you receive. Further on I patched into the output of the amp using a stereo jack to create a headphone jack that cut out the speaker when headphones are plugged in as well as a few other nifty features.

Parts List:

-NES Controller (to harvest parts from)
-8x momentary switches
-8x 47k resistors
-16 pin dip socket (optional)

This is a complex subject based on the system you are modifying. Newer generation consoles use many different parts, switches, and micro controllers, so it will be up to you to research or find out how to modify them to suit your needs.

One method that may work is to just mount the entire controller board inside your portable although this is really hard to work around and unless you make a custom case it will become very uncomfortable to hold. Another method is to cut the PCB along the least populated areas and then rewire any traces which you cut. This will allow you to rearrange the controller half's into areas of your portable which is more comfortable to hold. The downside to this is that as you move up in console generations the PCB for the controllers get more and more populated with traces and more complex, so this method will be difficult to work with.

The final way, which I will show, is only meant to be used on the most simple of controllers as it basically requires you to completely rebuild the controller from scratch. First you will need to crack open the NES controller to harvest the IC from it to use with your custom controllers. I suggest using a heat gun or torch for this seeing how heading up all the pins with an iron is near impossible. Another way to remove it is to score and snap the PCB until you only have the IC and then attempt to remove the remaining PCB with pliers and a soldering iron.

Actual construction of this controller is going to be hard to explain so reliance upon the schematic is going to be a must. Basically all of one side of the switches lead to a common rail which leads to the brown pin on the IC as well as the bottom pin on the left hand side. Then the other side of the switches wire up to one side resistors and follow through to their respective pins on the IC. From there the other side of the resistors are wired together and into the white pin. In the schematic the only side that is shown is the D-pad, although the A/B/Start/Select pad is wired the same way and then soldered onto their corresponding pins on the IC which I have marked because the original schematic did not have them. I found that if you keep the resistors as close to the switches as possible it helps reduce the size of the board. Also using IDE cable ribbon to join the two boards is the easiest/cleanest way I've found so far to join the two half's together. Once you get your controller boards soldered together, you can take the pins labeled with colors and solder them to their appropriate solder points on the games PCB for player 1. I don't have a picture of this unfortunately (or at least one that will make this step any clearer because I was using non color coded wires), but if you look at the existing plug you can easily figure which colors go where on the board. At first I was using the existing plug interface on the console, but I ran out of room in my case so I took them off and soldered wires directly to the console PCB. If you can design your own case I highly recommend using the existing ports because not only can you disconnect your controller for other projects, but you can include a female controller port on your portable attached to player 2 so you can play with a friend.

Parts List:

-Project box (or other form of case)
-Screws
-Glue
-Hard plastic (like credit cards)
-SPST switches (single post single throw)
-Stereo audio jacks

Finally it is time to put it all together and add other functions.

I used a premade project box, and trust me it was a big mistake. It was hard enough to find one close to the right size, but in the end it was to small. If you can 3D print a box, fiberglass with molds, or even glue plexiglass together do it. Nothing is worse than putting in all the work and finding out it doesn't fit right.

Anyways besides the box which will have to be dremeled out, there are certain things that need to be created and modded. One of which is the switches for the A/B/Start/Select buttons. If you noticed there is nothing preventing the buttons from falling out of your box. In order to solve this I simply cut up strips of old plastic cards that were a bit longer then the buttons and glued them to the bottom of the red buttons so they act as tabs. Installing this from the inside of the case results in the plastic buttons not falling out because the tabs hit the case on the inside. The D-pad though does not require this because it is circular in shape, and the cut out is a cross.

As for other wiring inside the case, it is pretty self explanatory. your voltage regulator goes to one side of your switch, the other side goes to your console and your screen. All your ground wires can be soldered into the consoles ground plain which makes it simple. From there it is only the basics that need to be wired such as the audio amp and video amp to the LCD. If you have been testing these components step by step for the most part they should already be wired and you just have to find a home for them inside the case.

Other mods that you can do to this project consist of two categories, motherboard mods, and self made component mods. One motherboard mod is the lockout mod that disables the lockout chip by cutting a pin off the lockout chip. This is a widely used mod and can be found anywhere on the internet. What it does is stop the lockout chip on the console from communicating to the lockout chip on the cartridge. The purpose of this being implemented by Nintendo was to prevent unlicensed and home brew games being played on their consoles. Unfortunately this chip also backfired with their original games as well causing the ever dreaded reset of death. By severing this connection you will have a better chance of the games loading the first time when playing. Another motherboard mod is a LED status light, which has mentioned in an earlier where you would solder a LED to the first and third pin on the old start/reset switch connector. This will allow you to see if your console is on (solid), or in reset status (blinking). There are a few slightly more advanced mods, which would work for the portable, but require some more research and engineering such as a potentiometer to adjust the speed of the games by adjusting the clock rate, as well as a stereo output mod which turns the NES's mono output into stereo.

As for component mods (the things we have created), you can wire in stereo jack into your audio amp between the output of the amp and the speaker so that you can insert headphones and the speaker will cut out. Another component mod is one which in theory should work but I haven't tested yet. Basically you put a stereo jack in between the video amp and the screen as well as wiring the audio out from the audio amp to one of the pins on the stereo jack. In theory this will allow you to create a 3.5mm to RCA wire so you can play your console on your TV still and when you insert your cable it will cut video to your LCD screen causing it to power down.

Overall, the steps are few when it comes to creating a portable console, although the more recent you go the more complex each step becomes. As long as you can thin out the console, replace/optimize audio/power/video amps and regulator size, and recreate the controllers to a portable size, you will be able to take almost any console and turn it into a portable.

Hopefully this has sparked some ideas for other portable projects or helped you create your own portable console/NES.