Hand-Held Legend Articles | Game Boy Modding – Hand Held Legend, LLC


Game Boy Pocket backlighting and 5v step-up regulators Dustin Hamilton - June 13 2019, 0 Comments

We want to address something that’s coming up frequently in the modding community… that the first impression of backlighting a Game Boy Pocket is disappointing. We get it. It doesn’t have to be, though, as the primary issue is brightness of the backlight - or sometimes the system simply behaving oddly or failing to stay powered-up.

Here’s the good news: this is an easily resolved problem… it may seem intimidating at first, but the solution is a 5v step-up (aka ‘boost’) voltage regulator. I’m going to cover not only the solution, but we’ll dive a bit into what’s happening and why the backlight is dim (or the system failing to work at all).


What’s going on here?

Simply enough the Pocket is awesome in that it’s very small, light, and is even powered by just 2 AAA batteries… and at the same time the issue is that, electrically speaking, it runs on very thin margins. Simply enough the main DC-DC convertor in the Pocket was designed to handle the system itself and using standard cartridges... there isn't enough margin for things like a hungry backlight and/or flash cartridge. While 2 AAA batteries add up to ~3.0v (alkaline), keep in mind that the system itself is using the bulk of that the batteries don't spend much time at the full 3.0v, either. The backlight is dim due to not getting sufficient voltage. Sometimes even, as mentioned, the system will behave oddly, visual anomalies, or even fail to stay powered-up at all… that depends on a number of factors, which I’ll skip for now to get at the solution.


Ok, so now what?

What’s needed is to boost the voltage supplied to the backlight, which is aptly named since the common name for the part is a 5v ‘boost’ [voltage] regulator… more formally known as a 5v step-up [voltage] regulator. These are rather small  PCBs (Printed Circuit Boards) but very important in function.

A 5v step-up regulator (I’ll call it a ‘boost’ going forward) does exactly what it says it does in that it takes voltage as low as 0.5v (per spec of our suggested boost) and ‘steps it up’ to a smooth and continuous 5v. The board I mention here is the Pololu U1V10F5 and measures only 0.35” wide x 0.45” tall (8.9mm x 11.5mm).


You can purchase the Polou U1V10F5 on their site currently for $4.49 USD (for 1) plus shipping: https://www.pololu.com/product/2115. You’ll need one to do this mod. Mind you this isn’t the only boost that will work, I simply find it to be the smallest and easiest to tuck away in consoles.



What’s we’re going to do is get the boost installed in a way that uses essentially straight battery power so that it does two things:

  1. Won’t strain the stock DC-DC regulator, which at 23 years old is likely showing its age.
  2. Providing the backlight its needed steady 5v power supply.



  • Soldering iron and supplies
  • Multimeter
  • Wire (30 gauge suggested)
  • Game Boy Pocket prepped for backlighting
  • Backlight
  • Resistor (if the backlight doesn’t have one built-in) It's very important to ensure you have the right resistor for the color of backlight you're installing!


Installation (presumes console open, etc)

Note: We’ll be placing the boost on the back of the speaker, so be sure to give yourself enough wire to do that.

  1. Start by soldering VCC from the Pocket’s regulator (middle-left solder point) to VIN on the boost.
  2. Solder GND from the Pocket’s regulator (lower-left solder point) to GND on the boost.
  3. Game Boy Pocket 5v DC-DC regulator 
  4. Check for continuity, while the console is off - you want to ensure you have a good connection between VCC and VIN, and between GND and GND. You do not want continuity between VCC and GND… if your meter gives a positive continuity indication (usually a beep/tone), then you’ve got a solder bridge and need to correct that before proceeding.
  5. Power on the console, and use your multimeter to measure the output of the boost between GND and VOUT, looking for a steady 5v (I usually see ~5.15v). If that looks solid and steady, power down the console lets move on.
  6. If your backlight does not have a built-in resistor, you’ll need the correct resistor for your color of backlight - check with the vendor if you're unsure. Solder the backlight POS (+, red) wire to VOUT on the boost… wire-in the resistor if needed. Note: Our Hand Held Legend V3 backlights have the resistor built-in; no external resistor is needed.
  7. Solder the GND (-, black) wire from the backlight to GND on the boost… you might have to re-solder this to ensure that both GND from the Pocket and GND from the backlight are soldered to this same GND point on the boost.
  8. Check for continuity again - you want continuity between POS (+, red) on the backlight and VOUT on the boost. You’ll also want continuity between GND (-, black) on the backlight and GND on the boost. Be sure to test for continuity between GND and VOUT - if you get a positive indication, you’ll need to correct that (usually a solder bridge) before proceeding.
  9. Power on the console - the backlight will power-on at this point and be at it’s full brightness, with the console doing it’s normal power-on procedure.

You’re all set regarding the backlight… now where to put this stuff? As mentioned briefly ahead of the wiring instructions, we’re going to place the boost on the back of the speaker - there’s a bit of room there, and the step-up is small, so it works out well. If you’ve placed your bivert module there, you can pick up our Pocket Bivert (link below) or relocate the bivert or the 5v step-up to another location in the Pocket (something not covered here, for brevity and focus).

Game Boy Pocket - Speaker back


Suggested: Recap

Especially if your console had difficulty staying powered-up or had other odd behavior when you first had the backlight installed, and to ensure top performance, you’ll want to replace the capacitors in your pocket… there are only four of them, so it’s an easy procedure. We don’t carry capacitor kits at this time, so head to Console5 (link below) for one from them at $1.29 USD at the time of this writing. It’s also an easy process - and we’ll get into detail in a later article.



Close up the console, now that we’ve tested everything and ensure it’s working, and you’re good-to-go!

Thank you once again, and keep those questions coming! We promise to do what we can to answer the most common questions to the best we’re able.


Product mentions


References and suggested viewing

Is the Game Boy a Computer? Colin (This Does Not Compute) - June 06 2016, 0 Comments

This is the first post in an occasional series by Colin from This Does Not Compute.

One of the things that has always interested me are devices that should be computers, but aren't really. We generally think of "computers" as multi-purpose systems, things that run an operating system and applications. But there are tons of devices out there that have processors and RAM but don't really run an operating system in the traditional sense. What is one very famous example of this that we are all familiar with? The Nintendo Game Boy series, specifically the original Game Boy, Game Boy Pocket, and Game Boy Color, sometimes referred to as the "DMG", "MGB" and "GBC" respectively.

I recently ran across the RealBoy emulator project (https://realboyemulator.wordpress.com). There are plenty of Game Boy emulators out there and this one isn't really any different... except for this excellent blog series that explains in depth how the original DMG works. It's meant as a primer in order to understand how the emulator's code works, but it's also an amazing look at the underlying hardware.

In short, the architecture of the Game Boy is pretty simple -- processor, RAM, and ROM. The first two reside in the console itself while the ROM (and some more RAM) is in the game cartridge. There's only a small amount of permanent code in the Game Boy hardware, basically just enough to get the device to perform an initial cartridge check. (The check is, in a way, a form of DRM; it makes sure that the game was licensed by Nintendo and not independently released).

The CPU is perhaps the most interesting part of the system. In the DMG, it's a Sharp LR35902. By all appearances it's a custom part, and in many ways it is, but designing an entire processor from the ground up just for a hand-held game system (or any game system at all really) isn't cost effective. So the Game Boy's CPU is actually based on the Zilog Z80, which was at that time -- and still is -- a common 8-bit processor. The Z80 itself was actually a binary-compatible version of the Intel 8080; not necessarily a clone, but capable of executing all the same instructions. There were some additions to the Z80 beyond that of the 8080, but the custom Sharp CPU wasn't just a rebadged Z80. It actually leveraged parts from both processor architectures, while omitting anything that wasn't relevant to a game console.

What to me at least, makes the Game Boy more of a device than a computer is that there was no traditional operating system layer, firmware, or anything standing in the way between the game and the hardware. After that initial check, the CPU simply ran any instructions presented to it by the game. Modern games are written using a high-level programming language like C, but older games were written in machine language telling the CPU exactly what to do and when. In some ways, the game itself was an operating system. (This is also partially why emulators aren't perfect -- you have to write high-level code that mimics how hardware works, whereas modern games, already written in a high-level language, can simply be ported to another platform)

You might be most surprised by the lineage of the Intel 8080. It was originally designed in 1974 (along with the Z80), and made its way into early PCs and even some arcade games like Space Invaders. But the 8080 also was the basis for subsequent Intel processors, like the 8086. The 8086 is where we get the common computer term "x86", as it spawned the 286, 386 and 486 CPUs. Those of course led to the Pentium series, and on to the modern processors we use in our computers today. It's crazy to think that in 1989 when it was released, the Game Boy actually shared some similarities with computers running Windows. It is in its own right, a computer... that also isn't.

This Does Not Compute is a YouTube channel (https://www.youtube.com/c/thisdoesnotcompute) about gaming, content creation and all things technology. Colin can be reached on Twitter @thisdoesnotcomp (https://www.twitter.com/thisdoesnotcomp) and Instagram (https://www.instagram.com/thisdoesnotcomp).

Update - Backlights - Game Gear - Buttons and Screens Kyle Capel - July 13 2015, 2 Comments

Here are a few updates for those of you who have been asking about when we will be restocked with various items. We will be away July 18th - 25th. Store will be open but orders won't go out until the 27th.

  • New Backlights Version 2.0: Completion date is set on the 24th of July. I hope to have them and available on August 1st. Sorry for the wati! Pushed back again...
  • Screens: Complete date was the 29th of June and is not the 27th of July...  hope to have them and available on August 1st. Sorry for the wati!
  • Buttons have been revised so the ETA here is August...
  • Game Gear/Lynx Backlights are back in stock
  • OSAKA LOCA order placed - and shipment is being prepared. Hope to start selling July 27th.
  • Clear GBC shells are on backorder. We hope to have a lot of them in by... (you guessed it) August... I HOPE

What other products would you like to see in the shop? Comment below.


New Backlight Sneak Peak Kyle Capel - July 07 2015, 3 Comments

Here are some photos of the new thinner backlight with a flat fcp cable. They look amazing! Colors even better in person, the pictures do not do it justice. Clocking in at 1.23mm, this is our thinnest backlight ever. No cutting required!!


... ...