iMac 24" reballing

I was practicing few months (~4 months) to prepare for repairing my iMac which went faulty. The problem was a manufacturing defect of Nvidia GPU chip. Every chip produced before 2008 was with that fault. So i have bought new chip with date 2010 (means free from any defects). It was laying on my desk until i gathered much skill to try to replace old one. As i said it took quite a long time which gave me huge patience lesson, 4 broken Xbox360 and 3 PS3. Still quite a good result considering the fact that I'm working on a very low end machines.

First attempt, i took of the old chip:

I did not bother to clean it properly (only core to make it easier then to take chip off by a suction pen), board was cleaned as properly as possible.

Then after old chip was taken off, I took all of the old solder from board and prepared it for putting new chip.

Chip in place ready to heat it up!

In this attempt, after new chip was in place, i tried if the process was successful, however iMac did not want to power on. I have read i should take it off and reball it again which i did, this time with lead solder. After all, i cleaned it all but this time, i did not put it back in, but left it to dry on the preheating device in a 120C for 20 minutes (as i used ISO PROPANOL Alcohol, wanted to make sure nothing left under chip or other parts soldered to the board). Pic of the graphics card with a new chip:

It worked! And i think i found the problem which emerged after first attempt, i think there could be some alcohol left in the board, causing short circuit. Anyway lead solder is better choice in solution in which temperature rises up and down very fast and often.

Pic of iMac working!:

I have done any stress testing to make sure it really works. It passed all! :)

Summary:

Chip cost me 60 pounds, repair cost 4 months of practice, many devices has been destroyed.

All devices needed to fix it cost around 300 pounds. 

Its still better than buy 'NEW' graphics card from ebay with old 2008 chip which will eventually fail.

Still i want to continue reballing as its my hobby now, which i really enjoy!

More reballing stuff soon, this time I might post some video if i will sort out some good camera.

Bye!