BGA Reballing Help Needed Please All Pro's Come

[Near123]

Hello Badcaps,

I have been trying to reball an Xbox 360 motherboard that i am having problems with.

Here is what i use

My bottom heater is a Griddle (i know it's getto it can get about 120c for bottom heat )
I have a proper hot air station as my top heater.
Also i sit right behind a window fan to exhaust all the fumes.

Now here is the Problem : Every time i try to lift the chip it fails. Let me explain I heat the board. I can only heat the chip to around 227c but anything above that will kill the chip. But for some reason i always have to go WAY above the following temp to remove the chip. Please if anyone knows why this is happening to me please i would greatly appreciate your help.

[WiseOldTroll]

Re: BGA Reballing Help Needed Please All Pro's Come

Your bottom heat needs to do more of the work. You should hit at least 150c on the top of the motherboard (measured with quality/accurate thermocouples/meters (Omega/Omega, or Omega/Fluke).

If you are not high enough on the bottom (120 vs. 150, or even as high as 170 for lead-free) you will have to go even higher on the top in order to get the heat through the chip, to the bottom of the chip/to the spheres in order to melt the solder. (Again, your bottom heat should do most of the work (75-80% of the melting point of the solder balls), and the top heat just enough to reach liquidus)

This is probably the largest contributor to the reason that you have to "go WAY above" the target temp in order to lift the chip.

Also, "I sit right behind a window fan...." can be an issue/contributing factor, especially now/in colder weather. Any (even slight) breeze can drop your temps quickly, and ruin the process.

How are you measuring the temp of the chip? 227 on top of the chip may not be sufficient enough to equal 217 at the spheres (under the chip) you may have to go a bit higher.
(Keep in mind how the effect of (not enough) lower heat works against you here. If your preheat/bottom heat is in the correct range, your top heat won't have to work as hard to reach liquidus under the chip).

If you are relying on the temperature setting (readout) of your rework station, the temp on the display will not be the same as the temp of the chip since it is measured inside the wand, and 100% of that heat will not reach/permeate the chip.

Even if you are using good/quality thermocouples/meters, the thermocouple needs to be as close to the chip as possible. Even so far as under the chip, if possible... if not possible, you should at least try to get the bead as close to, or touching the chip (two thermocouples (one on each side) are better than one). You should shield the thermocouple bead(s) with kapton tape, or flux in order to get a more accurate reading of the actual chip temperature (at least until become familiar with your/your equipment's capabilities)

Use enough/good quality flux under the chip (the better quality, the better the end result will be).

Search (Google) for the "nudge test" and learn to use it properly. Even with accurate measuring tools, the nudge test (if/when performed properly) will let you know when the temperature has become sufficient that the solder underneath the chip is liquidus, and the chip is ready to be lifted (liquidus, plus a few seconds will give you a clean lift)

I assume you bought a "Presto" griddle from Wal-Mart? And put screws in from the bottom to mount the motherboard? If so, you may need to move the motherboard closer to the surface of the griddle in order to hit 150c. (again, top of the board, near the target chip, not underneath the board). I'd advise abandoning the griddle as soon as possible and getting a proper preheater.

What (brand/type) "proper rework station" are you using for top heat? Does it have a proper size nozzle that matches the size of the chip, heats the entire chip? Are you holding the wand in you hand, or do you have a holding fixture/device to maintain the proper distance from the chip?

When you say "every time I try to lift the chip, it fails"---- IF you have tried several times, (and the target board is the one you are actually trying to repair) you have probably already killed the target package (chip).. as they usually do not tolerate more than 3 heating cycles before they die.

Which is why:

I would strongly advise getting your hands on (at least) a couple of scrap boards to practice on before attempting an actual repair.

Good luck.

[Near123]

Re: BGA Reballing Help Needed Please All Pro's Come

Wow thank you so much for the reply.

I was coming to the same conclusion about not having enough bottom heat. The griddle is only good for about 120c that only when i have it closest to the griddle.

As for all the items i am using during the process of lifting the chip.

1. kingbo flux
2. Suction pen (sorry i think thats what it called.)
3. a home made hot air wand holder
4. $20 thermocouple from amazon
5. bought a hot air station from ebay says 852D+ (but this was from china not not really some awesome brand. What i meant buy using a proper rework station was that i wasn't using a heat gun or some hair dryer)
6. a presto griddle (wow how did u know?)

I will try to give as much information as possible for my process. I leave the griddle on max with the motherboard on top while sitting behind the window fan. This heats the motherboard to 120c. I take the readings from the thermocouple. Also i have noticed that the hot air station does not produce the amount of heat that it says. That's why i don't really pay attention to that . I used to use only one of the wires from the thermocouple but on my last reball process i used both. I think i will stick to using both from now on. I stick them on top of the chip i am trying to reball.

As for the amount of time's i have reballed. So far i have killed 6 motherboards. I also have a lot of Xbox 360 motherboard that i can try to fix.

But i think my main problem is that i need a better bottom heater. I don't want to spend a whole lot of money but i think i have something in mind. It's called T8280 IR Preheating Oven infrared. Let me know what you think?

[dellxps15]

Re: BGA Reballing Help Needed Please All Pro's Come

hi, do you wantto do xbox with that hot hair ?
for me:
1: ok
2: vacuum pen ok
3: maybe ok
4: no good
5: no good
6:what is that ?

1) change hot air station.. that for smd not bga, or at least if u ddidnt kill almost 100 board before get into it

[Near123]

Re: BGA Reballing Help Needed Please All Pro's Come

I have seen people use Hot air station's for reballing. I actually want to succeed with hot air before i even think about spending big money on better equipment. For right now the only thing i want to change from the setup is the griddle. Btw a griddle is something you cook pancakes on .

[xboxhaxorz]

Re: BGA Reballing Help Needed Please All Pro's Come

hi, do you wantto do xbox with that hot hair ?
for me:
1: ok
2: vacuum pen ok
3: maybe ok
4: no good
5: no good
6:what is that ?

1) change hot air station.. that for smd not bga, or at least if u ddidnt kill almost 100 board before get into it

this is an intelligent dude
SMT and BGA are 2 different things

I have seen people use Hot air station's for reballing. I actually want to succeed with hot air before i even think about spending big money on better equipment. For right now the only thing i want to change from the setup is the griddle. Btw a griddle is something you cook pancakes on .

Yes and also with hair dryers, toaster ovens, torches etc; doesnt mean its right just cause many do it that way

http://www.thebgareworkmachine.com/b...ir-smt-repair/

I CAN tighten a tire with an incorrect socket and drive it around but when i go on the highway boom, im dead lol

Same thing using improper tools, the board WILL probably work but for how long and the chances you will ruin the board are even higher due to uneven heating temperatures

[xboxhaxorz]

Re: BGA Reballing Help Needed Please All Pro's Come

Also you asked for Pro advice, so if you dont want to take it then i recommend asking non pros for help

[dj_ricoh]

Re: BGA Reballing Help Needed Please All Pro's Come

hi, do you wantto do xbox with that hot hair ?
for me:



6:what is that ?

the new bottom heater! Make some and a while its heating and you reball the chip

[dellxps15]

Re: BGA Reballing Help Needed Please All Pro's Come

lool @dj ricoh


another tips i can advice you are:

1)if u make your own a bga rework station, u have to spent time in hardware setup and then in practice time.

2)if u start with a good bga rework station, u have only to spent some time in practice.


and also remember that lift a chip is only the first step. the second big one is to make ball in it and that part is really hard when chip are big and when u have to use 0.35mm balls .

then the final step is to solder it back and hope everything has gone ok.

so for me get some money as i wrote in other thread for bga rework and all other component that are also a bit expensive ehen added in the bga rework price list

also keep in mind that u wont get or learn any money in the next 4-6 or more months after that big purchace for practice.

[reaper57]

Re: BGA Reballing Help Needed Please All Pro's Come

Non pro advice here! If you want higher preheat temps then use the plates on top of most ovens (I don't remember what they are called :P). You can go a lot higher with these, but you are going to need something to distribute the heat with. I've done a few somewhat successful reflows with this method, and a few reball attempts all of which ended up with pulled pads off either the gpu, motherboard or both! If you want to get into reball get a rework station, it can be a cheap and hot air based one, but it's still going to be much better than a heat gun and an oven or any sort of paint removing or cooking equipment!