Saturday, November 19, 2022

Re-Modding a Game Boy

One day, while browsing through a local collectibles store, I came across some Game Boys.  I saw that two of these Game Boys were unusual and decided to bring one home to play with.  With this Game Boy I was able to fill a small but nagging hole in my handheld console collection.  So in today's blog post, I will discuss an unusual Game Boy to find in the wild and what I did to fix and improve it.

Before I talk about the Game Boy, I would like to talk a bit about the collectibles store.  Normally when you go into an antiques or collectibles store, you would assume that the items for sale are owned by the store.  This store was different, it was more like a co-op.  Various items in the store had stickers or tags on them with initials indicating the owner.  The owner sets the price of the item and writes it on the sticker.  When you bought something, the store clerk would write down a description of the item and ring up the sale.  At some point thereafter the owner and the store would split the sale price.  

The Game Boy with its Original Mods
At least one of the individuals who uses the store to sell his property is a gamer.  I have bought a few things in the store, but a few weeks ago I saw some items that were unusual.  A rather large number of video game handhelds and all-in-ones had been added to the shelves, and while most were too new to be of any interest to me, there were also three DMGs, a GBC and a GBA.  One of the DMGs looked stock but very yellowed and the GBA and GBC were unremarkable.  Two of the DMGs had been modded, one with a Prosound mod and one with a knob and a dial whose purpose I could not figure out while in the store.  Their shells were not quite-stock Nintendo shells.

What interested me the most was that both units had a backlight mod installed.  Now in the past I had tried and failed, multiple times, to mod Game Boys with a backlight.  One time I cracked the screen, another time I tore the ribbon and a third time I caused dead lines in the center which I did not know how to fix permanently.  More recently I was able to restore the last Game Boy I tried to backlight but broke the screen.  The CPU board is where the heart of the machine lies and that was good, so I installed a replacement screen and LCD board, a new case and such and the result was a fully working and restored Game Boy.  

The first time I went to the store I had no batteries, so I came back a few days later with batteries to test the systems.  The DMG with the Prosound was selling for $10 more than the one with the mysterious knobs.  The backlight seemed stronger with the Prosound unit, so I decided to save a little money and take home the the cheaper unit.  

When I got home I found out why this was the cheaper unit.  The polarization filter had been placed to show inverse video, and I thought that made the screen difficult to see with the backlight.  However, when I opened up the unit I discovered that the backlight was not showing any light at all.  The other unit at the store did show light, but that unit had not had a bivert mod installed, so contrast left much to be desired.  No bivert mod was in this unit either.  It had been wired in correctly so I assume it had burnt itself out.  There was a resistor in the strip with the LEDs, so the backlight panel had not been burnt out by incompetence.  Rotating the polarizer screen 90° restored the original pea-soup green color to the screen and made it a little easier to see.  The blue LED is not stock, blue LEDs did not exist during the DMG's lifespan, DMGs came with red LEDs.

The mysterious switch and dial turned out to be a variable clock speed mod.  The switch enables or disables the mod and the dial adjusts the clock speed output by the Game Boy's 4.194MHz clock crystal.  This can overclock or underclock the system, but if you underclock the system too much, the screen will start to flicker too much and will no longer show graphics.  In order to fit the mod, the modder had to drill a pair of holes in the top of the system to access the button and the dial.  

The front half of the shell turned out to be a normal gray shell which had been painted blue.  It was obvious that the completely white screen lens and the buttons were not stock components.  The rear shell looked to be an original clear shell from the "Play it Loud" line.  The battery cover was also painted blue as was the inside RF shield, strangely enough.  A fair number of original screws were missing.

Having fully inspected this DMG, I found it hard to believe my luck in that I found a system for such a reasonable price that was fully ready for a backlight installation.  The most difficult part of the backlight mod is removing the reflective and rear polarizer layers, but someone else had done this and was successful, sparing me the trouble.  I resolved to not only fix the existing mod but improve it as well as refashion the console to satisfy my own aesthetic tastes.  The existing mods were too dated anyway and the paint job seems to predate the easy availability of replacement shells.

In order to get the parts I needed, I had to shop around.  This was not my first rodeo, my previous experience with a full mod had conditioned me to expect that I'd need to tap more than one resource to obtain all the parts I needed.  Hand Held Legend (HHL) had the best selection of backlights, and I ordered a yellow-green v3 backlight because that color most closely matches the original color of the unbacklit screen.  They also distribute the CleanPower DMG DC-Regulator Board v2.0 from RetroSix.  These boards improve battery life, reduce audio noise and make life a little easier for the DMG in its twilight years.  Retro Modding (RM) has a unique bivert board that is smaller than other boards.  I had difficulty the last time I tried installing a bivert board with video issues, but that board was larger.  

The shells on offer from HHL and RM were not particularly inspiring.  I wanted a clear shell but one that had the Nintendo GAME BOY logo on the front.  Apparently the trend is to not put the logo on the front of the shell, perhaps due to pressure from Nintendo.  Neither HHL nor RM had shells with that logo, but Retro Game Repair Shop did, so I ordered the shell from them.  Their "Factory A" shells came with membranes, buttons and screws, although I was not expecting great quality from throw-ins.  I forgot to order a replacement for the blue LED, so I won't get a less bright signal for low battery.  I had a pair of glass LCD screen lenses so I did not order any, but the lens I used shows more border than it should, I think it was meant for a modern display.  Modern display mods have a slightly larger active pixel area than an original DMG screen.  

Having to order from three separate suppliers meant that shipping costs were higher than it would have been if I could only order from one supplier.  For this rather modest bill of materials I had to pay $65.76.  If I had to replace the screen, as I did for last year's mod, it would have cost me about $100.  

Once all the parts had been delivered I replaced the DC Regulator Board, a process which was manageable without using desoldering braid or pump.  By applying heat to the end of the pins on the LCD board ribbon cable connector, I was able to lift the two pins on that connector for the bivert board using a craft knife.  I put the bivert board underneath, tacked it down to the points on the PCB where it is anchored and then bent the pins back over the pads, pushed them in and soldered them.  It is not impossible to break these pins by applying the force required to lift them from their pads.  I removed the dead backlight from underneath the LCD glass screen, soldered wires to the new backlight panel and fit it underneath the LCD glass.  The wires were soldered onto either side of the capacitor below the ribbon.  Then the polarizer was rotated 90° and placed between the LCD glass and the backlight panel.  The polarization gives the LCD screen a characteristic navy blue look when the screen is off.

The Game Boy after my Mods
The last stage of the modding process is also the most frustrating after the process of removing the reflective and rear polarizer layers of the original screen.  The LCD and CPU printed circuit boards have to be screwed down into their respective halves of the shell.  The standoffs into which the screws go in are not predrilled, so you have to use tremendous force to cut threads into these holes by screwing the screws in manually.  You can strip screws or screw holes if you are not careful and there are twenty screw holes to fill.

My mods were successful, although I reused a D-Pad from an original console because it had a larger pivot underneath than the replacement D-Pad.  I found the start and select buttons are too short and I will replace them with original buttons.  I may also replace the A and B button membrane.  The RetroSix shell I used for my previous Game Boy mod had a small "For" above "Nintendo GAME BOY", which I find to be a distraction.  This "Factory A" shell does not and feels to be more authentic.  The "Factory A" shells are not molded for IPS screen mods such as the one my previous DMG has.  

So how does a backlit and biverted original screen compare to a stock screen and an RIPS v4 OSD Backlight Mod Kit?  The RIPS uses a modern LCD display designed for cellphones.  Well, once you see the backlit biverted screen in action, it is very hard to go back to a stock screen.  The bivert mod does a tremendous job of improving contrast and it does not notably improve vertical streaks you can sometimes see on these screens, at least with the DMG's screen.  You might see a little flicker here and there with some games that rapidly alternate between shades to show intermediate colors, but modern displays will show a distracting amount of flicker.  Due to the slow LCD pixel refresh of the original screens, the screen is a little blurry with moving objects compared to a modern display.  The backlight's lighting is not perfectly even across the screen, leading to characteristic humps at the bottom of the screen.

Other benefits to performing a backlight mod to an original screen is that you keep the system nearly 100% Nintendo and the backlight and bivert mods are cheaper than a screen replacement.  You can save about $35 by backlighting the original screen.  The downsides to backlighting the original screen are that you can easily ruin the screen, there is more soldering to do and the soldering is more difficult.  

It cost me just under $110 to buy this Game Boy and mod it to something I can be happy with.  That might seem expensive but that gets you a fully working system with the ability to use a flash cart like the EverDrive GB X7 regardless of lighting conditions.  Here is the photo gallery of this Game Boy with its original mods and this photo gallery shows the Game Boy after my mods.

Three Game Boys: Stock DMG, Backlit Original Screen, Backlit Replacement Screen