Complete repair guide for Game Boy games.

game boy game repair guide

Has your Game Boy Game stopped working? Is there a problem saving, garbled display or just a plain white screen? In this guide I have listed all the methods I know on how to resurrect failing and broken Game Boy cartridges. The good news is most CAN be saved!

So, how do you repair a Game Boy cartridge? To repair a Game Boy cartridge, you will need to open your cartridge, clean the board and contacts and if that doesn’t help them you can move onto reflowing the solder around the Mask ROM and SRAM chips.

How do you open a Game Boy Cartridge?

To open a Game Boy Cartridge, you will need a 3.8mm Game-bit. These are cheaply picked up online I recommend that every game enthusiast picks up a set of both 3.8mm & 4.5mm bits as these are the most commonly used bits in retro game carts and consoles. You can check the prices on Amazon here

game boy game repair guide

The screw is on the back of the Game Boy cartridge and once out the game shell slides apart for access to games PCB.

game boy games repair

Identifying your problem

If the inside is completely filthy, then that could be your problem. Clean the board the best you can with isopropyl alcohol and a cotton swab paying close attention to the metal pins at the bottom of the cartridge. If they are very grimy you can use an artist’s eraser to gently rub up and down along the pins. 9 times out of ten this will fix the garbled text or back bar instead of the Nintendo Logo on startup.

If this doesn’t help, then you can also try to clean out the Game Boy’s cartridge slot. This can be done using a cotton swab or an old t-shirt covered in a small amount of isopropyl alcohol. You can use an old store card to simulate a cart being inserted. Another option is to pick up an officially licensed cleaning kit by Nintendo.

This black bar or jumbled text means the Game Boy is having a really hard time reading the game data and the game won’t initialize in the bootrom. It runs the code against what is stored in the BIOS ROM and if it matches it boots the game and if it doesn’t the game won’t boot.

Overview of a Game Boy Cartridge

If you are still having problems, then it’s worth having a look at the board. The picture below is from Pokémon Silver, some other games will look different inside, but most are similar. Let’s have a look at the function of each part of the Game Boy cartridge, this will help us to understand whatever problem we are facing.

game boy repair guide overview

1. Mask Rom

The Mask Rom is where the game data is stored. You may have heard people mention game ROM’s before, this stands for read-only memory and is the actual file containing all the code of your game. This is usually the cause of games that have glitchy graphics, text and music. This would be the first thing I would check if the Nintendo Logo was not displaying correctly on boot.

2. SRAM

The SRAM is where your save file is stored. The SRAM requires constant power to keep your save ‘Alive’. These days save data is handled by Flash memory keeping your data safe regardless of power.

3. The MBC3 Chip

MBC stands for Memory Bank Controller. Originally, the Game Boy could only access 32KB of ROM data at a time. Any additional data would need to be moved into MBC using a method called Bank Switching. This allows the game data to be read in smaller chunks. Various MBC chips exist depending on the size of the game. In Pokémon silver, we have the MBC3.

The MBC3 chip is what controls the Real Time Clock, Pokémon Gold, Silver and Crystal use this to keep the games day and night cycle functioning. To have a working RTC the cart must also have an external 32.768 kHz Quartz Oscillator (Found in the top left corner of the cart). One more requirement is that the cartridge contains an external battery, this ensures the RTC can continue ‘ticking’ even when the game is not in a console turned on.

If you are having issues with the RTC your best bet would be to reflow the solder of the MBC3 paying special attention to pins 19 & 20 as these are where the signal is brought in from the oscillator. If that doesn’t work, you can try to resolder the resistor labelled R2 just below the oscillator.

4. MM1134 Chip

The MM1134 chip controls when the SRAM is powered from the Battery or draws power from the Game Boy. If you are experiencing a white screen on boot, then the MM1134 chip is usually the culprit. A simple reflowing of the pins around the chip should fix most white screen issues.

5. Save Battery

Before Flash memory became the standard, we used to use lithium batteries. (How barbaric.) This provides constant power to the SRAM and will last around 15 or even 20 years, in some cases. Games like Pokémon Silver, gold etc, or any that use a Real Time Clock will drain the battery much faster. My Pokémon red copy is still going strong! If your game cannot hold a save anymore then this will need to be replaced.

How to tell if a Game Boy Game’s battery has died?

If you have any problems with saving the game your battery has most likely died. On the Pokémon games, I find the Real Time Clock starts to act up just before total battery failure. To be sure the best way to check is to use a multi-meter to see if there is any power coming from the battery. The standard battery is 3V so you should expect to see ranges from 3v – 3.3v.

As you can see from my copy of Pokémon Silver the battery is completely dead. (RIP Celebi from August 29th 2001 Toys R us event!)

How to replace a Game Boy cartridge battery? The correct way.

I have seen some degenerates using knives, tape and all sorts of craziness to switch the batteries in Game Boy carts. Don’t be that guy.

The correct way to replace a Game Boy cartridge battery is with a soldering iron. You simply heat up the solder on either side of the battery and lift the battery up using some tweezers.

game boy battery removal guide

Go over to Amazon or eBay and grab yourself some replacement cell batteries with tabs. (Make sure they have tabs!). Most Game Boy cart batteries are CR2025 & Game Boy Color usually have the slightly smaller CR1616 installed. Make sure you check the type you need before picking any up. The board usually has the size listed above the battery.

Once your battery is in place you can load up with a little extra solder to secure your new battery in place. Make sure the battery is oriented the correct way. The + & – symbols are on the board in case you forget!

game boy game new battery
game boy voltage test

Optional: There is no reason that you cannot replace a CR2025 with a bigger CR2032. Both output 3V, the 2032 is a little bigger than the 2025 at 3.2mm which will still allow enough clearance to close the cartridge. This will provide a much longer battery life so is well worth doing. Unfortunately, I am out of CR2032, so I will have to make do with a 2025.

How can I back up my Game Boy saves?

Removing the battery will sadly delete whatever you have stored in you SRAM (Losing you save file basically!). There are ways of circumventing this, however, if your save is already gone then you’re out of luck!

The first method would be to purchase a Mega Memory Card or a Joey Joebags by Benn Venn (Yes, real name). The Mega Memory card will let you plug in your cart and make a back up of your save. This is the safest and easiest way to back up your save file.

The Joey Joebags is more full-featured and allows you to dump your Mask Rom, SRAM and even actually allows you to write data to certain types of carts. It also supports GBA games. You can drag and drop your save data and even RTC data.

Secondly, it is possible to unsolder and resolder a new battery why the game is plugged in and console turned on. Please take the utmost caution if using this method. You will need a GBA or GBA SP to have clearance on the back of the cart. Insert your cartridge half assembled as shown below and de-solder your old battery, then re-solder a new battery.

Wait a minute or so for the solder to cool and see if you can save, if all has gone well you will be able to save. Turn the console off for 30 seconds or so then back on and see if you have managed to save your game. Obviously, this method is for lunatics and I do not recommend it. The chances of something going wrong are much higher when messing around with live electronics, try this at your own risk.

One last method would be soldering an ‘Interim’ battery in parallel to ensure that no power is lost to the SRAM while removing the failing battery and installing a new one. Doing this on a Game Boy cart is VERY difficult, you usually only have two points of contact being the solder pads where you will be removing the failing battery from. You could connect some cables and run them from the interim battery, but personally, I wouldn’t even recommend trying this method.

The game won’t save at all and there is no battery?

This happened to me. Way back in August 1999. I was thirteen years old on holiday with my parents in the Canary Islands, I, of course, had my Game Boy Color with me I was gifted for my birthday earlier in the year. While walking around a shady Spanish mall we stumbled upon a video game / electronic store, inside was a display cabinet of Game Boy & Game Boy Color games. One of the games was Pokémon Blue. Now, I had been following the gaming news in magazines about this Pocket monsters game for some time and was eagerly waiting for it to be released in the UK (Was released until Oct.5 1999, 3 and a half years after Japan).

Immediately spent my ‘holiday money’ on Pokémon and went back to our rented villa and had a great time. Played past the second gym, saved my game and called it quits. The next day I turned on my Game Boy Colour and couldn’t seem to find the save?

Turns out the copy I purchased was not an American import like I had assumed but in fact a very convincing bootleg game. The game had a box, insert but no manual. Also, the game cart was grey, which I didn’t know at the time that all Pokémon games came in coloured carts.

To save on costs some counterfeit games don’t come with batteries soldered. Be careful about what you are purchasing. Most ‘modern’ bootlegs are obvious as they usually have the word ‘GAME’ written on top of the cart instead of ‘Nintendo GAME BOY TM’

How to repair the Mask Rom of a Game Boy Game

If you load up a game and it won’t boot, try to clean the pins first as listed above, but if its one of the rare cases where that will not fix then we will need to look at the game’s PCB directly.

Game Boy games are two layered PCB which is less than 1mm thick. What can happen is that constant flexing of this very thin PCB, from cycling the games in and out of the cartridge slot, can cause microscopic breaks in the solder around the legs of the Mask Rom and SRAM. You can fix this by reflowing or adding a little more solder to the legs.

thin PCB gameboy
game boy games guide repairs
game boy games repair guide logo

As you can see I have this problem with this Game Boy Color game. Initially, the game wouldn’t read at all and displayed a black bar, after cleaning the pins the game almost loaded but was still showing corruption of the Nintendo Logo (Read error). Fun fact: the more jumbled and distorted the logo is, the harder time the Game Boy is having reading your cartridge.

To repair this, I opened the game and applied some flux to the pins. I added a tiny bit of solder to the tip of my soldering iron and dragged it down the legs of the game. I did both sides and thankfully did not have to do the SRAM.

game boy cart flux
game boy rom solder

Let the solder dry for a moment before putting the game back together. This is the same method I would use if the game was displaying glitchy graphics or text etc.

game boy color repair

1 thought on “Complete repair guide for Game Boy games.”

  1. Amazing read and guide bet my pokemon death squad have bit the bullet already though and are beyond saving 🙁

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