Replacing BGA components with hot air.

[Spork Schivago]

Re: Replacing BGA components with hot air.

hot air is more professional manufacturers using hot air more than infra.
on rsx most of the time the pads are oxidised.
you have to remove the shim while the bga is on the board this is the trickiest part.
then prehet the board for 80C and then start new profile for removing the melting point on lead free alloy is between 230-240 you have to use good flux below the bga.
there are 4 tiny cap on each corner of the rsx you can remove this you don't need it as you going to weld back the bga without shim so basically there is no weight that will splash the balls.
the wetting point on leaded is max 220 for not more than 30 sec.
also you have to tin the pads back with paste that is aggressive to the pads this create nice shiny contacts.

So, with a preheater and a hot air rework station, but no BGA rework station, it is possible to replace the RSX chip?

From what I can tell, the only reason it might not work is the temperature profiles. I was thinking of trying to mod my WHA900 hot air rework station and replace the knobs that control the flow rate and temperature with a digital version. Just use the parts from the WHA900 and through them in a new case, design a circuit board so it'd be digital for temp / flow rate, and show the temp / flow rate on a screen maybe...

[gigimorphe]

Re: Replacing BGA components with hot air.

hot air is more professional manufacturers using hot air more than infra.
on rsx most of the time the pads are oxidised.
you have to remove the shim while the bga is on the board this is the trickiest part.
then prehet the board for 80C and then start new profile for removing the melting point on lead free alloy is between 230-240 you have to use good flux below the bga.
there are 4 tiny cap on each corner of the rsx you can remove this you don't need it as you going to weld back the bga without shim so basically there is no weight that will splash the balls.
the wetting point on leaded is max 220 for not more than 30 sec.
also you have to tin the pads back with paste that is aggressive to the pads this create nice shiny contacts.

[Spork Schivago]

Re: Replacing BGA components with hot air.

PS3s need bottom heat as well as top. Whilst a bought machine is easier to use (I have a Scotle IR machine or a clone of one) there are people making their own.
Ease of use would include the storing of different profiles, unleaded and lead, the ability to watch the temperature curve against the profile on an external screen is also nice.

When you say bottom heat, do you just mean the whole board gets preheated or do you mean the bottom board gets preheated and then there's concentrated heat where the BGA chip is on the bottom and on top as well?

[diif]

Re: Replacing BGA components with hot air.

PS3s need bottom heat as well as top. Whilst a bought machine is easier to use (I have a Scotle IR machine or a clone of one) there are people making their own.
Ease of use would include the storing of different profiles, unleaded and lead, the ability to watch the temperature curve against the profile on an external screen is also nice.

[stj]

Re: Replacing BGA components with hot air.

he does reflow, reballing or replacement.
whatever is needed, he also does laptops.

this place is out of your area, but gives you a good idea of kit and materials etc.
the shop owner is a forum member
http://www.bgareworkstore.com/

[Spork Schivago]

Re: Replacing BGA components with hot air.

you can do ps3 / xbox360 with hot air, a friend does them with an achi unit.
IR pre-heaters under the board, hot-air on top.

What does he do with the PS3 / 360's? Does he just heat up the chips so the solder underneath melts or has he actually replaced a BGA component on a PS3 / 360?

Also, do you know what ACHI unit he's using? Is it the IR6000 or maybe the IR6500?

[stj]

Re: Replacing BGA components with hot air.

you can do ps3 / xbox360 with hot air, a friend does them with an achi unit.
IR pre-heaters under the board, hot-air on top.

[Spork Schivago]

Re: Replacing BGA components with hot air.

Stefan Payne,

I'd like to revisit this topic again. I've been doing some more research into BGA rework and I see they do make some hot air reballers, like the Weller WQB 4000 SOPS.

Why is it impossible to replace a BGA component without a machine specifically made for BGA rework? I'm not questioning you, I just want to understand. I originally thought it was because you needed IR instead of hot air, but seeing how there's hot air reballers, I'm guessing that's not the reason...

Is it because of the temperature profiles? Or maybe because of how hard it might be to line up the component? I'd just like a bit more information on this. Thank you.

[Spork Schivago]

Re: Replacing BGA components with hot air.

No, it's almost impossible without a BGA rework station.

And those things just cost too much...

Thank you. Yes, they are expensive. I wanted to try and find plans for an open-source, open-hardware version but was unsuccessful in my search, at least for a real nice professional type one.

[Stefan Payne]

Re: Replacing BGA components with hot air.

No, it's almost impossible without a BGA rework station.

And those things just cost too much...

[Spork Schivago]

Has anyone successfully replaced any BGA components using a hot air rework station? I have a broken PS3 there and was thinking of replacing the RSX chip. It's a BGA component and I don't have a reballer. I was thinking maybe removing the old chip, cleaning the pads with desoldering wick, purchasing a stencil, balls and a new RSX chip. Then I was going to try using a k-type thermocouple to monitor the temperature the best I could and try to hold the temps for however long the profile for the chip says. Would this work? Has anyone tried it before?

I've had a little success with these things by just holding the hot air over the chip to the solder melts under it. But the fix never lasts long. No more than a month or so.