Broke a logic board trace fixing a simple capacitor swap

I was working on a 2012 MacBook Pro logic board last week, just replacing a bulging capacitor near the CPU. Thought I had the heat gun temp dialed in at 350C, but I must have held it too long on one spot. After the swap, the laptop powered on but wouldn't recognize the trackpad. Turns out I melted a tiny trace underneath the capacitor that went to the trackpad controller. Spent 3 hours running a jumper wire to fix it, learned the hard way to always check the board underside with a scope first. Anyone else been burned by hidden traces under surface mount parts?

2 comments

2 Comments

cooper.reese17h ago

Honestly I read somewhere that Apple boards from that era have this weird thing where they use multiple layers of ground plane that make hidden traces way more common than you'd expect. I think it was a forum post where a guy described finding a trace under a capacitor that was totally invisible from the top side even with a magnifier. 350C sounds about right but the trick I heard is to keep the heat gun moving in circles and never hold it still for more than 5 seconds on any one spot. Three hours on a jumper is rough but at least you saved the board, I've seen people toss whole MacBooks over stuff like that.

grant.parker18h ago

Always hurts when the fix creates a new problem, man. I've been there with a stubborn GPU capacitor on an old Dell board and found out later the trace ran right under a tiny resistor I had to remove. Feels like the board is just messing with you sometimes (you know, just to keep things interesting). Glad you caught it though, three hours on a jumper is a win compared to trashing the whole board.