I found a very yellow, though otherwise good condition DMG Gameboy in the ewaste bin at the local supermarket last November 2019. (I often have a quick scan in there, to see if there is anything worth using) I was pleasantly surprised to see the Gameboy in there, and brought him home. As you can see, it booted fine with no game cart, though it was horrifically yellowed:
After a good clean, it was time to correct the yellowed plastic:
I took it to a friend who has an indoor retro-briting set up: we were in early winter at this point, with minimum UV rays outside. After a few days treatment, it had improved, though the UV was not strong enough to turn all the yellow around. At this point the case was misplaced for a few weeks, eventually reappearing at a third party's house.
In the meanwhile I had added some mods to the gameboy, and was ready for more retrobriting. However, I had to wait for the sun to come out again! After two more days BAKING in neat 12% hydrogen peroxide with full on sunlight, the yellow was finally banished from the case.
After studying the subject extensively; I find this really is the best way to retrobrite:
Submerge the work completely, in as close to neat 12% peroxide as you can get. Use a small plastic (clear) box to reduce the amount of liquid needed to submerge. You can add water, though remember: every ten millilitres will reduce the strength percentage by 1%). Using liquid (instead of painting creme peroxide on) guarantees a streak free finish. Cover with cling film to slow evaporation and put in a spot which gets sunlight all day long. A very sunny day is needed for the reaction to take place. You can use blu tak to stick down and submerge small parts like buttons, or battery cover. It seems unaffected by the chemicals.
I plan to use the DMG largely for sound, so I added yet more mods to the gameboy. I opted for a large pot to control the clock speed, as I find it more expressive to turn a larger pot.
I chose the Black glass screen because the original grey one I bought was too large for the case. The vendor said this was common, and I'd only have the same issue with a replacement. I went for black instead, from the Play it Loud Gameboy series (which the vendor replaced for free, thanks Carl!) I'm very happy with the look. The backlit screen though, is bulky, and the screen area does bulge a little.
The full mods list: DC Jack converted to charge port.
Made charging cable (from USB cable).
Rechargeable LiPo battery installed.
New rubber button contacts.
Glass lens.
Polarizing screen.
Pixel Bivert mod board.
Backlight in green. (most original look)
Colour corrected / Retrobrited plastic case.
Clock speed adjustment circuit and control pot. I use these clocks from circuitbenders:
Clock switch (original / adjustable)
New amplifier installed. I used PAM8403H. It's meant to drive speakers really, it's fine though.
Original amplifier disabled (cut 5v connection)
Volume pot removed.
Bypass capacitor installed across 5v line.
To Do:
Needs a boost board inside to help out the original 30 year old circuit. I added so many things which use 5v: the light, the amp, the pixel mod, the clock circuit. The boost circuit is getting hot boosting the 3.7v battery voltage up to 5v for all these extras. (so hot you can feel it through the case!)
Now I just need to get a cart for this and try out some synth tones. Oh, and build an arduinoboy to control it over midi : )
Finished DMG, looking amazing:
Here are a couple of videos, in development and finished: