I have bought a Gameboy Pocket for around £25. It was broken when I got it, the unit wouldn't power on and drawed 0 amps. I have tried the usual suspects; the power switch often gets corroded inside, and needs to be cleaned; the contrast wheel might also need some de-oxit or isopropyl alcohol to show an image; but to no avail.
I started probing around the motherboard, making sure that there is continuity from the battery springs to other parts of the motherboard. Everything seemed to be fine, but I noticed no continuity between the GND points on the board, and the battery - contact. After some digging around the Internet, I have found someone who reverse engineered the Gameboy DMG and Pocket, and made up a schematic. (Credit to Gekkio, the schematics can be found here.) The schematic showed continuity from battery - and GND, and a small jumper wire from the battery contact to the GND pad on the voltage regulator board got the Pocket working perfectly. It even works fine with my Everdrive clone, I have heard that Pockets can struggle with flashcarts sometimes.
The next thing I need to do is to retrobright this thing, the transparent shell has a bit of a yellow tinge that I can remove. I have bought some 12% cream hydrogen peroxide, and a UV lamp to try it out. I remember watching a YouTube video where someone did this to a clear shell, with very good results. I will update you all later.
The hydrogen peroxide cream has arrived. I've bought a 12% cream oxidiser, which should be good enough for the job. I think this stuff is intended for bleaching hair, but I like my colour so I won't dare try that. The procedure is simple, in theory: you paint the shell with the peroxide cream, wrap it in cling film to stop the cream from evaporating, then leave it in the UV light until the shell is no longer yellow (I'm not sure for how long but I can figure that out I guess.) I want to keep this Pocket as stock as possible, so I will try to cover up the stickers on the back with some masking tape to hopefully stop them being destroyed.
I coated the top and bottom shell of the Pocket, wrapped it up in cling film and stuck it under my 2 UV lights. Annoyingly, my power bank with 2 USB's couldn't power the two LED strips, I can't imagine they take that much current that the powerbank would protect itself. Luckily, my old PC that I probably should throw away saved the day. I strongly reccomend that you wear gloves while doing this, I didn't and the tips of my fingers are all stained white. It'll go away soon, but it can't be doing great things to my skin. I've read somewhere that there's no need to cover up the stickers, which is great because I ran out of masking tape, and electrical tape would probably be too strong and leave a lot of adhesive behind. You can always get replacements for those stickers, but I have way too many modded consoles and a purely stock console is a nice change of pace. It's really hard to get used the old reflective screens after being spoilt with IPS mods and backlights for so long.
I have left the Pocket baking for roughly 1 and a half days, a half day was out in the natural sunlight (a rarity over here!) and the rest was under my USB UV lights, which did an okay job but the sun is a lot faster. The shell is still a tad bit yellow, but it's good enough for me (gotta stop being such a perfectionist :D) It matches fairly well with the battery cover, which I bought new. The serial number sticker made it through the hydrogen peroxide (just needed to be glued back on,) however the model no. sticker has delaminated slightly. I have decided to break my 100% stock rule slightly (I guess I already did that with the battery cover...) and buy a replacement sticker, along with a glass screen protector, as the OEM plastic one as some very deep scratches in it. No backlight tho! I'm very happy with this thing, and so is my mum. Might give it to her one day, she loves Tetris. I have plenty of the peroxide cream left, and it will definitely come useful again. It seems to be doing a good job, and I would recommend it.
I gave this Pocket to my mother in the end, along with a copy of Tetris. She's really happy, and if she's happy then I'm happy too.