Hit 1000 reflows on one BGA chip this week with no fails

So I've been practicing BGA rework on these old Xbox 360 boards for a while now. Last Tuesday I finally crossed 1000 reflows on the same chip and it still boots up every time. I used a cheap Chinese preheater and a hot air station from Amazon, nothing fancy. The trick was getting the profile right - I preheat at 150C for 3 minutes then ramp up slow. Before this I was killing chips left and right from thermal shock. Has anyone else tracked their success rate on a specific rework job like this?

2 comments

2 Comments

avery72111h ago

My buddy Dave tried this exact thing on some PS4 boards last summer. He thought he had the profile dialed in but skipped the slow ramp part, ended up popping six chips off in a row like popcorn. He still has the scar on his thumb from where one landed on him. Last I checked he was down to maybe 200 reflows before a failure, but he's too stubborn to change his technique.

riley583h ago

Honestly 200 reflows sounds almost impossible unless he's running some seriously low temp solder or his definition of "failure" is super loose lol. Most guys I've seen who skip the preheat get maybe 50 tops before a joint cracks or the chip lifts. That scar story is rough though, I've had a few fly off but never bad enough to draw blood. The real trick is the ramp rate more than anything else, even a good profile won't save you if you're heating too fast. Dave might need to stop being stubborn and just borrow someone's datalogger for an afternoon.

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