Hey guys, sorry for being a noob but I need some help.
I’m working on a project where I am replacing one BGA chip with another. Its basically a memory upgrade. I keep getting stuck though and I don’t know where I am going wrong. Maybe someone can help me?
I remove the old chip by preheating the board and then using hot air. This goes fine, no missing pads, perfect.
I clean up the board using flux and wick. Nothing special there.
I have the new chips and this is where some of my confusion is coming in. I didn’t think they came preballed but I am not so sure. When I clean up an old chip, there is nothing that looks like pins but on the new chip there is. Are these solder balls or do the pins “melt” is heat is applied?
I have a reballing kit and screen just for these chips. I did manage to get solder balls on the new chips a couple times but it didn’t look right and it didn’t work right.
I apply tacky flux to the board, nothing else.
Preheat the board, then use hot air to gently seat the new chip.
Here are my questions:
Do chips generally come preballed?
Do the pins on the bottom of the chips melt if heat is applied to them?
Should I be putting anything else on the board besides tacky flux? A couple people mentioned using solder paste.
What the heck am I doing wrong?
Here are some pics of what I am using:
The board
https://lh5.googleusercontent.com/-JgGs … G_0059.JPG
The chip (although fuzzy, its only 6x8mm)
https://lh3.googleusercontent.com/-uGAw … G_0060.JPG
tools and stuff
