New Year, New Game Boy

by Jon

One of my many hobbies is collecting and playing retro video games, especially portable / handheld systems, and especially those from Nintendo. I try to get one of every model where I can, however my rule is to only ever buy systems that I actually intend to play.

A couple years ago I bought an original Game Boy that had been modded with a backlit screen. I didn’t have an original Game Boy in my collection, and the mod itself, while inexpensive, involved a very delicate peeling apart of the original LCD and replacing specific layers – something I did not feel up to doing. So I bought a finished one off eBay.

But at the end of the day, it was just, okay.

What I hadn’t realized was that the backlight changed the color palette from pea-soup green to a gradient of blues over white. It worked, but it took a lot of the charm out of the system. Also, while the modder had replaced the original lens with a nice, scratch-resistant glass one, it didn’t sit flush with the system. The edge stuck up sloppily along one side, and it would catch my finger when I wiped it off.

I decided to accept it for what it was, but it did spend more time on the shelf than my other handhelds. When I did take it down to play, I started noticing weird splotches under the lens. I assumed it was water condensation getting inside, but it turned out to be pressure marks from the unevenly applied lens pressing against the LCD underneath. I didn’t know how to fix it, so it spent more and more time on the shelf.

Then, finally, when I took it out this past winter, it wouldn’t even turn on. The power LED lit up, but not the screen, and there was no sound. It was, for all intents and purposes, dead.

I started to think maybe it was going to just be an unfortunate shelf piece – with so many other smaller and lighter models to choose from, I didn’t really need an original to play. But the modding scene today is further along than it was a couple years ago, and the latest innovation has been a slew of drop-in replacement IPS LCDs.

I’m also a lot more proficient at repairing and restoring vintage electronics than I was a couple years ago. So I decided to take the plunge and try and rescue my poor dead Game Boy. I hit up Hand Held Legend and ordered a fancy new IPS display kit.

Since the system wouldn’t turn on I also picked up a set of replacement capacitors, and as some people complained that the IPS screen introduces some noise into the audio output, I also picked up the proscribed audio amp.

With all the parts in hand, the first step was to open the system up and remove the old backlight mod.

As you can see, the system separates into two parts – the front board with the LCD and buttons, and the back board with CPU and batteries. The new kit comes with an entirely new front board, so I set the old one aside for now and focused on the back board.

At the top was a “bivert chip” that needed to be removed. See, just adding a backlight to the original LCD produces a very washed out image – but modders figured out that if you rotated the polarizer (one of the LCD layers I mentioned before) it produced better contrast, but inverted the image. So they created a bivert chip to invert the image to start with – the result being the correct image with good contrast.

The chip was pretty easy to remove, the hard part was where a few pins from the LCD ribbon cable connector had been bent up off the board to connect to the chip. It was very finicky work to bend the pins back down and resolder them without touching the other pins.

After the chip was out I removed a set of patch wires connecting to the headphone jack. I vaguely remember the original listing for the system saying it had some kind of audio mod, but I couldn’t for the life of me figure out what they’d actually done, other than re-route some wires.

In fact, I was annoyed at the quality of the work – the soldering was weak and held on with globs of hot glue, and they’d straight up snipped some of the original wires.

Thankfully I asked around online, and a modder was kind enough to explain that it was called the “Pro Sound mod” where the audio to the headphone jack was re-routed to avoid the noise from adding the backlight. They also explained that the “IPS causes noise” issue was overblown, and that I probably should try out the existing mod before wasting time installing the new audio amp.

So I took their advice and reapplied the Pro Sound mod to my own soldering standards.

Now that that was done, I set about putting together the new IPS kit. As per their instructions, I connected everything together without permanently mounting it, and fired it up to make sure it hadn’t been damaged during shipping.

It didn’t work.

It gave me the same problem as before – power LED lit up, but no screen, no sound. Just to be sure, I re-attached the old front board, with the same results.

So, assuming the new screen and front board I’d just bought were good, then something was wrong in the other half. Assuming it was a leaked capacitor, and thankful I’d bought replacements, I took out the back board to check.

But it looked absolutely fine. I gave it a good cleaning with some isopropyl alcohol, but still no dice. So it was time for the multimeter. I started poking around the board and found no obvious shorts, and looking at some schematics online, found plenty of points where there should have been power, but registered nothing.

That’s when I learned that the little board in the bottom left wasn’t part of the audio circuitry, but the main power board. Taking a closer look, I could see where some previous battery acid leakage had escaped the battery compartment, and gotten all over the power board.

I cleaned it off and started testing, and while it looked pretty bad, the only real damage was to the trace from the input voltage (the batteries or AC adapter) to the rest of the circuit. So I patched a wire across the two pins and crossed my fingers.

Success! The original front board lit up just fine (though inverted, since the bivert chip was gone). Now that power board may not last forever, and I may need to replace it entirely in the future, but after a couple hours of cleaning and troubleshooting I was more than ready to finish this project.

The penultimate steps were to install the new front board in the front shell. This required making some minor alterations to the inside of the shell, including trimming some posts that would be in the way of the new screen, which is actually larger than what appears through the viewport.

This was also when I saw why the previous lens didn’t sit properly – the plastic lip that it attaches to was covered in uneven globs of glue. The replacement lens I’d bought already came with its own pre-applied double-sided tape, so I just took the time to sand away all of the old glue and even out the surface.

After all that prep, it was finally time to install the new board and permanently affix everything into place. The new screen is mostly held in proper alignment by a bracket, but it’s also taped to the shell forming a seal to keep out dust.

Ah, dust. With everything screwed together, the last thing to do was to install the new glass lens, which meant getting the LCD as clean as possible. After everything else, this was the most nerve-racking part of the install. I knew once the new lens was on, any bit of dust, any smudge on the LCD, would be out of reach.

I spent a long time painstakingly wiping away specks with a microfiber cloth, using cans of compressed air, and reevaluating the screen at different angles. When I was finally ready, I quickly peeled the seal off the new glass lens and applied it straight away.

Victory! I’d done it! I’d saved my poor dead Game Boy. The buzzing concerns were unwarranted – only on the highest volumes to the speakers buzz slightly, and the headphones don’t buzz at all. Everything worked perfectly, and there’s no way this is going back on my shelf any time soon.

Anyway, I hope you enjoyed this little project,

/jon