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Showing posts from December, 2018

Fixing cracked solder balls under a BGA package

I got another pack of failed Xbox One controllers. Most of them had classic problems like broken LT frames,(which by the way I could not find anywhere) broken analog sticks and broken internal board-to-board connectors. I noticed that one of these controllers was the strangest of all. Everything working fine with this controller except the LT and the Y axis of the left analog stick. I walked through my regular troubleshooting process and I didn't find anything unusual wrong. It discovered later that was a cracked solder ball under the main controller chip. The crack was probably caused by a strong external force like a drop or a bend. As I continued repairing this poor gizmo, I realized if I pushed the IC to the board with my finger I get the right values on my tester and everything seems to work as it should. This ment that the cracked balls maybe fixable by a reflow so I reflowed the chip but it did not worked. I wanted to try to fix it by doing a reball, but I don't have p