Original Xbox 128MB RAM upgrade

A couple years ago I attempted to upgrade the RAM in an original Xbox from 64MB to 128MB. That attempt wasn’t a success. More recently I tried the original Xbox 128MB RAM upgrade again, this time successfully. This post covers the process of upgrading the RAM in the original Xbox. I cover what I did wrong with my first attempt, and how I was able to successfully upgrade the RAM with my second attempt.

What’s the point of upgrading the RAM?

Original Xbox 128MB RAM upgrade

The truth about upgrading the RAM in an original Xbox is that it isn’t incredibly useful. You don’t really see any benefits while playing retail games or anything like that. There are however some benefits of upgrading the RAM.

  1. There are some Sega Chihiro arcade games that work on original Xbox consoles with 128MB of RAM. Those games include:
    1. Crazy Taxi High Roller
    2. Ghost Squad
    3. Gundam Battle Operating Simulator
    4. Ollie King
    5. Outrun 2
    6. Sega Club Golf 2006 Next Tours
    7. Sega Network Taisen Mahjong MJ 2 and 3
    8. The House of the Dead III
    9. Virtua Cop 3
    10. Ford Racing Full Blown
    11. Wangan Midnight Maximum Tune 1 and 2
  2. Many emulators on original Xbox can take advantage of 128MB of RAM
  3. Game debugging performance is improved (Xbox development kits had 128MB of RAM).

So an original Xbox 128MB RAM upgrade isn’t quite as useful as a hardmod or softmod for the system. It’s more of a mod for those who want to try out those Sega arcade games, run additional emulators, or get into Xbox game development.

Things you’ll need

Original Xbox

There are several ways to perform this upgrade. This is a list of the things I used to upgrade my console.

Step 0. Sourcing original Xbox RAM chips

Original Xbox RAM chips

To upgrade the RAM in your original Xbox you’ll need to get your hands on four extra RAM chips. There are two main ways to do this.

The first way to get extra RAM chips is to remove them from another original Xbox board. This is what I did because I already had a broken original Xbox board. The downside of this method is that you need to sacrifice an original Xbox, and that there’s a chance the RAM will be damaged if you heat it up too much while desoldering it.

From my understanding all of the RAM from any original Xbox is compatible with any other original Xbox. In my case I was able to put Samsung K4D263238F-QC50 RAM into a system that originally had Samsung K4D263238D-QC50 RAM.

Original Xbox removed RAM chips

Removing RAM from an original Xbox is pretty simple. Just heat up the pins of the RAM chip with a hot air rework station, then remove the chip when the solder melts enough. Using flux can help, but it isn’t really necessary.

The other way to get extra RAM chips is to purchase them from the internet. I don’t know any US suppliers that supply compatible RAM chips at a decent price, but there are tons of Chinese suppliers that do. Just search a place like eBay or AliExpress for the model number of the RAM chips that are inside your console.

Step 1. Installing XBlast OS for RAM chip testing

This is a very important step if you want your installation to be less frustrating. I didn’t do this the first time I attempted to upgrade the RAM, but did the second time. Basically what you need to do is install the XBlast OS BIOS onto your system. This BIOS allows you to boot with any number of RAM chips installed, and allows you to test each chip individually.

A normal Xbox BIOS will only boot with exactly 4 or exactly 8 perfectly installed RAM chips. With XBlast OS as long as you don’t have any serious shorts you’ll be able to boot. Meaning that you’ll be able to install a single chip and test it before moving on to the next chip. That removes a lot of guess work and troubleshooting and makes things so much easier.

I’m not going to explain how exactly to install XBlast OS. Here’s a link to the XBlast OS project page. If you’ve ever flashed a BIOS to your Xbox before it’s pretty much the same process. There’s a crcwell.bin file in the OS zip file which you can flash to your BIOS chip.

Note that XBlast OS isn’t something you’ll want to keep on your Xbox once you’re finished upgrading the RAM. At the moment it has very limited functionality and can’t play original Xbox games. So you might want to take a dump of your BIOS so it’s easier to flash it back when done.

Step 2. RAM chip installation

In its default configuration the original Xbox will have two RAM chips on the top side of the board, and two on the bottom side of the board. To upgrade the RAM you’ll need to solder two chips onto the top, and two chips onto the bottom. You can install them in any order, but I found the chips on the bottom to be easier to install because there weren’t any components like capacitors or heatsinks in the way. So you might want to start on the bottom and work your way up.

The process of installing each chip is pretty much the same, so I’m just going to cover installing a single chip. Just repeat steps 2 and 3 for each of the four chips.

Some boards already have a small amount of solder applied to the RAM chip pads. My board didn’t, but if it did there would be a fairly obvious small bump in each pad. If there is you can choose whether or not you’d like to remove it using solder wick. Just be careful not to apply any pressure, or use too much heat, since you risk ripping off a pad.

Original Xbox RAM orientation

Next you’ll want to align the RAM chip in its correct orientation. Each chip should have the same orientation as the chip right next to it. With my chips there is also a smaller circle engraving on the chip that aligns with the corner with a small white circle on the silkscreen of the Xbox board.

Original Xbox tinned RAM pad

With the RAM chip aligned you’ll want to  pre-tin one corner pad of the board with a little bit of solder. Then put the RAM chip back on top of the board making sure to align it over top of the pads as closely as possible. Then you can solder that one corner pin to the pre-tinned pad.

Original Xbox RAM soldered corners

Recheck the alignment and make any adjustments if needed. You can make very small adjustments without needing to heat up the solder in the corner. Bigger adjustments will require heating up the solder in the corner. I find that keeping a finger pushed down on the chip during this whole process is useful in keeping things centered. Once the chip is fully aligned solder the opposite corner pin to the pad.

Original Xbox RAM flux

Now you can solder the rest of the pins to the board. Apply flux to all of the pins, don’t worry about applying too much, the more the better. Once the flux is applied carefully apply a small amount of solder to the tip of your soldering iron, and drag it across the pins. You’ll want to both drag across the pins from pin to pin, as well as drag down the pins from the top of the pin down to the edge of the pad. I did the dragging process in both directions several times before it was the way I wanted.

Original Xbox RAM upgrade

The goal is to apply an even coating of solder to each pin that forms a nice solid connection with the pad. It’s better to use not enough solder and add more later than it is to apply too much solder and have a hard time removing it. If you add too much solder it may work itself out as you repeat the dragging process focusing on bridged or cold connections. If it doesn’t you may need to use a little bit of solder wick to remove some solder.

Repeat this process for each of the four sides of the chip. You’ll likely start to get a feel for how much solder each side needs as you get more practice. Once you think the RAM chip is properly soldered move on to the RAM chip testing phase.

Step 3. RAM chip testing

XBlast OS boot menu

Once you’ve installed a RAM chip you’ll want to test it. Before you do that you’ll want to clean off as much flux as you can using isopropanol and a brush. Then you can put the board into the console. You don’t need to connect everything, just the power supply connector, power button connector, and controller port connectors. Then you can plug in the power supply into an outlet, and the console into a TV.

XBlast OS settings

XBlast OS tools

Turn on the console and you’ll see the XBlast OS boot menu. If you don’t then chances are you caused some sort of short on the board that needs to be fixed. Select the settings menu, then select tools, then select the 128MB RAM test.

XBlast OS 128MB RAM test

The 128MB RAM test tool will go through each RAM chip and test it. It may take a while, especially when you’ve installed all four chips. It will either say success or failed for each chip. If the test fails for the chip you are trying to install then you’ll need to rework it. If it succeeds you can move on to installing the next chip.

XBlast OS RAM upgrade success

I had to rework the first RAM chip I installed, but was able to get the others working on my first try. A good way to diagnose the chip is to use tweezers and try to wiggle each pin (you can also sort of just run the tweezers along the pins and feel out any movement). If a pin wiggles or moves in any way it’s loose and needs to be soldered. You might also want to look around for any potential solder bridges and correct them. If you aren’t having any luck at all you might want to try reapplying flux to all of the pins and reflowing them with your soldering iron again.

Step 4. Finishing up the Xbox 128MB RAM upgrade

Original Xbox 128MB RAM upgrade

Once all four RAM chips have been tested you can completely put back together your system. You’ll want to reflash your BIOS of choice, but make sure it supports 128MB of RAM (most of the more modern ones do, but you should double check).

What I did wrong the first time

A couple years ago when I first tried to upgrade the RAM in the Xbox I didn’t have any luck. The system wasn’t able to boot no matter how many times I tried to rework the RAM chips.

One of the key things I didn’t do was use XBlast OS and test each RAM chip as I went. This is super useful since it isn’t an all or nothing installation. If a single chip doesn’t work you can see that and rework just that single chip. It removes a lot of the guess work.

The other problem I ran into was just not using the right tools, primarily from a lack of experience. I attempted to use a heat gun to reflow the RAM chips onto the existing solder on the board. In theory this should work, but it didn’t. A hot air rework station would have been a better tool for that method since it would allow a more focused flow of heat.

I found that the drag soldering method really is the ideal method for upgrading the RAM in an original Xbox.

Conclusion

Original Xbox 128MB RAM upgrade

By using drag soldering, and XBlast OS, upgrading the RAM in an original Xbox is actually a fairly quick and easy process. To be honest the benefits of having more RAM aren’t great, but it’s still a fun project if you have some spare time and want to fill those empty RAM pads on your console’s main board.

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I’m wondering if you installed the N64 Amp with the mindset that it would be using TTL Sync or 75Ohm with termination? When I look at the mod, it’s almost as if it’s for TTL Sync, since it’s missing the 75OHm termination at R43. Did you bridge this connection instead and go with TTL Sync? I’m a little confused because you mentioned that you weren’t using the built in Amplifier in the 64, which makes sense.. but wouldn’t it require 75Ohm termination unless you used the built in Amp? I’m trying to do the same mod but I’ve botched a… Read more »