Electronic – Hole in PCB due to corrosive reaction

corrosionpcb

I have an Xbox One controller where the X button did not work anymore. I disassembled it today, to find the reason for this. It turns out, there is a hole in the motherboard near the X button:

Hole in Motherboard

There was this sticker right above the hole (it seems that "XJY" is an abbreviation of "Shenzhen Xinjiaye Electronics Technology Co., Ltd.", which is a chinese company that builds such motherboards):

Sticker

Now to my question: is it possible that the adhesive of the sticker in combination with the flowing electricity on the motherboard has caused a corrosive reaction, resulting in the hole? I think there is no mechanical cause, since the wires in the hole are still largely intact and the "missing" part of the motherboard was not inside the controller.

Best Answer

It's unlikely.

  • The hole is very nearly circular, and has smooth edges, indicating the hole was deliberately drilled.

  • Somebody has added thin wires to try to repair the damage, indicating the defect was found and "repaired" before the product left the factory.

Most likely the hole is meant for mounting the board into the housing. The damage to the surface layers is a fabrication defect that they tried to fix rather than scrapping the board.

Edit: As pointed out in comments, another possibility is that the hole was drilled deliberately to remove some incorrectly designed wires, and then the added wires you see were added to replace the connections broken by the drill.