Reflow BGA package?

[DaveC]

I'd like to replace an old microprocessor that is a BGA package. New they are
$170-plus, but I can find old ones in laptops for almost free.

Is it possible to re-flow old BGA packages or is this not possible?

BTW, I found this study on stencils which (I think) says they're not
necessarily all that effective:

<http://tinyurl.com/ny5p52>

Thanks,

 

[Martin Riddle]

I'd like to replace an old microprocessor that is a BGA package. New
they are
$170-plus, but I can find old ones in laptops for almost free.

Is it possible to re-flow old BGA packages or is this not possible?

BTW, I found this study on stencils which (I think) says they're not
necessarily all that effective:

<http://tinyurl.com/ny5p52>

Thanks,

Yes you can but it costs. Once the BGA is removed, it needs to be
reballed.
Then reflowed, xrayed and inspected, and repeated if it failed
inspection.
One major hurdle is the thermal profile. Was the BGA the first part or
the last part?
Components on the bottom?
It gets really complicated, I doubt you'd find someone willing to do
this for 1 piece.

Cheers

 

[DaveC]

It gets really complicated, I doubt you'd find someone willing to do
this for 1 piece.

There is a place in Main, USA, that is reported to do this, one-off.

But I was considering doing it myself. The hot-plate or electric griddle
technique ($30 at Walmart). Googling around shows many successes. But with a
BGA I've yet to see it.

 

[Archimedes' Lever]

I'd like to replace an old microprocessor that is a BGA package. New they are
$170-plus, but I can find old ones in laptops for almost free.

Is it possible to re-flow old BGA packages or is this not possible?

BTW, I found this study on stencils which (I think) says they're not
necessarily all that effective:

<http://tinyurl.com/ny5p52>

Thanks,

Your best bet would be to find a lab that has an SMD rework station.

Sure, YOU can reflow a laptop chip, and removes it, and you can reflow
the bad chip and remove it, but re-using the replacement requires
specific steps.

Also, the rework station is ideal for the removal on the PCB you are
trying to fix, as hap-hazard reflow techniques can cause failures to
other components local to the removed part. That is why a rework station
is practically a requisite. You could call a few contract manufacturers
that do PCB assembly, and ask them what they would charge you to change
out a chip with no guarantees. Finding someone to perform that task for
less than $50 will not be easy. Also, it is all very likely RoHS, so
lead free processes have to be used, and that is an even higher temp.

 

[Archimedes' Lever]

There is a place in Main, USA, that is reported to do this, one-off.

But I was considering doing it myself. The hot-plate or electric griddle
technique ($30 at Walmart). Googling around shows many successes. But with a
BGA I've yet to see it.

You would have better success with a more focused heat source that a
griddle plate.

Particularly if there are other SMD parts surrounding it, and there no
doubt is.

You bring the whole assembly up to about 160 F. Then, you apply some
heat to the bottom, directly under the chip, to bring that part of the
board up a couple hundred more degrees, then you place the focused heat
on top over the chip, all the while preparing to grab it with good
tweezers or a four corner mechanism that you build specifically for
removing the chip.

You cannot pull the chip before all the balls reflow, and you cannot
"pull" at all really. If the temps are right, it will reflow, and you
should be able to lift it off with NO force required, and you should
never apply any either.

I would still get someone with a rework station to replace it though.

The surface has to be prepped after the old chip comes off, and other
things that require someone with experience to perform to keep from
buggering up the board.

You may succeed, but the odds are below 50%, and decrease another 10%
with each additional 25 balls.

Even when done in a pro lab, it is difficult, and x-rays are required
after.

 

[Archimedes' Lever]

It's a relatively straightforward procedure, given the correct
equipment. X-ray isn't *required* especially for a on-off like this.

It IS required if the replacement does not work.

 

[Reflow Guy]

Walmart and BGA repair don't mix

YES - it is possible to do BGA rework, but not something to make a home remedy for.

First, you have to establish a reflow profile for the part that won't warp the board. Pre-heat, soak and reflow based on whether your technology used Pb or Pb free solder.

Once the part is removed, you have to reball it.

Then you have to precisely place the BGA back on the PCB and execute the heat profile again.

If you want to try this with a Walmart griddle, be prepared to throw away $30 for the griddle and the board (unless you like pancakes). No one would touch this work for less than about $250. It would take half the day to repair a one off item like this and that is WITH the proper lab equipment.

 

[Reflow Guy]

Here's an example of the proper equipment needed for
BGA Rework