Your Eyes Are Your Best Tools
Alisha C -
At some point, this Xbox controller stopped powering up, or at least it stopped powering up when you used the button. It would still come on if you connected to USB, and even stay on if you removed the cable. But the Xbox button did nothing. Curiously, it worked just fine once the controller was on. But it didn't turn the controller on, or power on the console.
This controller sat on my shelf for months. I dissected it probably three or four times before I found the problem. I just lived with it like that for a while—we have other controllers. If I couldn't find any of the other ones, then connect this controller to a spare USB port for long enough to get it to power up, and away you go.
When I first opened it up, I saw some mild corrosion(?) on the board, but nothing on any components, just bare PCB and some solder points for the shoulder buttons. I cleaned it all up thinking maybe that had interfered, it was near that area of the board. Nope. Same issue.
Then I thought I fixed it with a firmware update. But no, that fix was just not having tested if the controller kept power once I disconnected the USB before I updated the firmware.
Ultimately, the key was realizing that the Xbox button seemed to be the actual problem. I ripped the whole thing down again to map out the board and see if I could find the issue. I pulled everything out and started looking at the contacts for the buttons. On either side of the Xbox button is a little via through to the other side of the PCB.
I found the corresponding hole on the flip side of the board and followed that trace to a resistor. I almost missed it, but I noticed that there didn't seem to be a connection between the board trace and the resistor any longer. Testing with my multimeter confirmed no continuity. It actually ended up being two separate traces, that had been eaten away, probably by the corrosion I originally found months and months ago.
I cleaned the area up a little better, and I soldered a tiny jumper wire to connect either end of the resistor to the two broken traces (and covered them over with some solder mask). Put the resistor back, resoldered the wires for the vibration motors that I probably tore off the top board about 6 times. Put everything back together, and it worked! Now I just need some new joystick caps (puppies......).
Not understanding the specifics of how a device works is not enough reason not to fix it. This repair was as simple as "See broke. Fix broke." It isn't always that easy, but common sense, sound reasoning and good observation skills go a long way, even without in depth knowledge of a device's inner workings, or schematics for the board.