Hey Everyone,
I picked up a Game Boy Micro that was in rough shape. It was listed on FaceBook Marketplace as working, but will not charge. It also came with an official Game Boy Micro Link cable, so that was pretty cool. When I got the device, it you install an already charged battery into the unit, it would play just like normal. However, the system will not charge the battery, the seller thought it was a bad charge port and that it might be a great candidate for a USB-C mode. I figured it was a fuse issue, seemed like a common fault. I took the system apart and tested the fuses, both are good. I don't see any board damage, nothing stands out. I tested with a couple known good batteries and chargers and no improvement. For the heck of it, I did do the USB-C mod with HDR's adapter PCB. IT looks great. I can plug in a powered USB-C cable and get voltage, but still no dice on charging. I did some online research and not sure what's left. I did find a photo online that shows the approximate voltage on several positions of the mainboard. I get some of the readings shown, I hadn't measured anything from the chip on the right side of the photo yet.
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I've highlighted in purple the voltages I get when measuring (or close to the voltage, as it varies based upon the batteries charge) the ones I haven't highlighted in purple are areas where I get 0V readings. To me, it looks like the voltage comes in from the charger, comes down to the D1 PS diode and then stops. I get the 4V on the right of the diode and 0V on the left side of it. I took my digital multimeter and set the dial to diode testing, and when I put the probes on the sides of the diode I get a reading of 000000 and if I switch the ends which probes are on, I still get a reading of 000000. From what I've seen on how to test diode YouTube videos, this is a sign of a shorted diode. So my current assumption is the diode is bad.
Only issue is, I have NO idea on what to order as a suitable diode replacement. Does any one know what diodes I can order to replace this bad one? On my main board it looks like the diode has the marking of "S3" on it, looking online I also see other variants that have ":2W" on the diode, but I'm unable to find anything about those online.
If I'm missing anything and I'm completely wrong, and this isn't signs of a failed diode, please let me know what else I can test, I really want to revive this system. I have 2 other Game Boy Micros (a normal black one with a silver faceplate, and a mint condition 20th anniversary/Famicom edition one) that are great shape and I don't like to use them as I want to preserve them, I was excited about this bad Game Boy Micro since it's in rough shape and I can just toss it in my pocket without a care and use it as my daily driver and with the bonus of a USB-C port, I don't have to worry about carrying around a proprietary charger for it, and USB-C charger will do.
Thanks in advance everyone! Hoping we can help save this system!
I've included photo's of the front and back of my PCB incase anyone can spot any potential issues.
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