Replacing BGA components with hot air.

[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.

[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]

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.

[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.

[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.

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.

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/

[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.

[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?

[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.

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...

[stj]

Re: Replacing BGA components with hot air.

i would not try that, you wont have profile control.

the proper units can raise and lower the heat in timed stages.

[Spork Schivago]

Re: Replacing BGA components with hot air.

i would not try that, you wont have profile control.

the proper units can raise and lower the heat in timed stages.

Right. I should have explained the original question a bit more in detail. The idea was if I could safely replace BGA components with hot air, I wanted to use my preheater and the Weller WHA900 Hot Air station parts and modify it into a BGA rework station. I wanted to use the hot air blower motor and redesign the circuit board, so I'd have profiles.

The first step would be designing the board that controls the motor to make it digital. Then I'd want to add some K-Type thermocouples. Finally, somehow hook it up to a PC to control it remotely so I could use profiles. Instead of saving up a lot of money and buying a BGA rework station. I'd still be able to use it manually for SMD type work. I just wanted to know if it was possible. I know it'd be a lot of work, but it could be very fun and one heck of a learning experience.

I believe these things have a PIC in them. The preheater does at least and I can control that remotely via an RS232 connection. My soldering station and "talk" to the preheater and I have the protocol information for the preheater. I thought I could implement the same protocol on the hot air rework station so the hot air could talk to the preheater and vice-versa and the computer could control both.

What do you think?

[Spork Schivago]

Re: Replacing BGA components with hot air.

i would not try that, you wont have profile control.

the proper units can raise and lower the heat in timed stages.

Hey! I think I saw some people using those controllers in their home made BGA rework stations. I was wondering if I should maybe purchase some of those to use in my attempt for a homemade hot air BGA rework station.

[stj]

Re: Replacing BGA components with hot air.

it's doable if your pre-heater is big enough and you fit your air unit into a drill-press type frame over it.

your not pre-heating under the chip btw, your pre-heating the whole board to avoid warping or cracked joints caused by hot and cold area's

personally i would just get a couple of pc400/410/900 controllers off ebay - they are designed for it.

[diif]

Re: Replacing BGA components with hot air.

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?

The whole of the bottom of the board gets heated. I cover any delicate parts like plastic connectors with aluminium/kapton tape.

Bottom heat is required for two reasons, having cold parts of the board and very hot causes warping and cracking and it also requires more effort from the top heater.

[Spork Schivago]

Re: Replacing BGA components with hot air.

...
personally i would just get a couple of pc400/410/900 controllers off ebay - they are designed for it.

Grab the PC400/410/900 controllers and hook them up to my Weller WHP-3000 preheater / Weller WHA-900 hot air blower motor?

If so, this would make it so I wouldn't have to design a custom circuit board for the hot air rework station blower motor, right?

[Spork Schivago]

Re: Replacing BGA components with hot air.

The whole of the bottom of the board gets heated. I cover any delicate parts like plastic connectors with aluminium/kapton tape.

Bottom heat is required for two reasons, having cold parts of the board and very hot causes warping and cracking and it also requires more effort from the top heater.

That's what I was thinking. It's just like when I do SMD type work. I preheat the board so it doesn't warp. I thought maybe for BGA though, they might need the whole board preheated and then extra heat on the bottom where the chip was going. It was a stupid thought though. Thanks for clearing it up for me.

[stj]

Re: Replacing BGA components with hot air.

Grab the PC400/410/900 controllers and hook them up to my Weller WHP-3000 preheater / Weller WHA-900 hot air blower motor?

If so, this would make it so I wouldn't have to design a custom circuit board for the hot air rework station blower motor, right?

exactly.

[stj]

Re: Replacing BGA components with hot air.

That's what I was thinking. It's just like when I do SMD type work. I preheat the board so it doesn't warp. I thought maybe for BGA though, they might need the whole board preheated and then extra heat on the bottom where the chip was going. It was a stupid thought though. Thanks for clearing it up for me.

some do have a 3rd heater that blows up under the chip.