Chosen Solution
I have two 3DS motherboards that I’m trying to troubleshoot, so that I can use at least one to replace another that’s in a bricked system. One of the MBs causes the well known ‘pops and turns off’ problem on boot (where a few seconds after being turned on, a popping sound can be heard, and the system immediately turns off). The other board simply fails to boot, with no backlights turning on for either screen (this one does not respond to any of the ‘forced’ functions, such as L+R+A+Up). I’ve been able to conclude that in both cases the problem is with the motherboard, as a third board was able to start with no issues in the 3DS. The cables had been seated several times to rule out those issues as well. In all cases, the SD card reader, nattery, L/R ribbon cables, WiFi card, infrared chip, top and bottom LCD, microphone, and C stick components were shared, so I’ve ruled them out as being causes. Both F1 and F2 fuses are shown to be working on both boards as well. Is there anything else I could possibly test to identify a solution? I hate wasting parts if they can be saved, especially the motherboard.
Here are your answers for both PCBs, they’re actually fine. Here’s the real problem and fix: Pop & Quick Shutdown PCBThis is due to the speaker/3D slider flex ribbon having a small nick in the ribbon near the joint. Finish tearing that system apart and remove the speaker ribbon from the joint. I’m 99% certain you’ll find a small cut in the ribbon similar to this: Small cut in 3DS speaker flex ribbonNo Backlight Boot PCBThis is due to a faulty lower LCD. I found (in the XL version at least) that when it fails to boot and sits at black screens & blue power indicator the lower LCD is faulty and needs to be swapped out. Take a working lower LCD screen and try it out to see if that gets the BSoD PCB to boot up again. I hope this helps getting your two systems running again. Good luck!
