it depends on what the problem was, it certainly doesn't hurt, but it isn't a miracle cure.
If a cold solder joint(crack/break) is the problem, it is a perfect cure. However, if the problem is a flaky part, reflowing will do nothing.
I'm sorry but the way you wrote it seems it fix any problem, it doesn't.
That's not what I said. "Cold solder ball joint" was specifically mentioned to distinguish between that and other problems.
It also isn't a permanent fix, it may fail in a month a year.
Yes, it is.
It can make the fix last longer depending on what the original problem was.
IF it was a cold solder joint, reflowing is a permanent fix.
There seems to be a lot of confusion on this subject, so let's be clear. Ball joints underneath a part package(chip or component) are soldered just like any other electronic part. If the joint was less than optimal at the factory, reflowing using a
proper liquid flux at
proper oven temps for a
proper amount of time will result in a permanent fix for a cold solder ball joint.
This is not magic, it is simple electronic know-how and physics.