OLinuXino Open Source Hardware Linux computer was designed to be Do-It-Yourself friendly Linux computer, but the more powerful versions contains BGA ICs.
Many people are afraid to try to solder BGA ICs and think, that this is very complicated process and require lot of expensive tools.
Indeed if you do mass production you need expensive and precise machines to place and reflow the boards which cost a lot of money.
If you have to assembly and repair small quantity of boards though you can do it with low cost equipment as well.
Sure you may broke some ICs and boards until you learn how to do this properly, but this should not discourage you.
In this tutorial we will show you how A20-OLinuXino with burned processor is repaired using only few low cost tools:
- hot air desoldering tool
- soldering iron
- twizzers
- solder wick
- tacky flux
- isopropile alcohol
all above cost total less than EUR 200
Step 1 – hold the IC with twizzers and move the hot air handle above the IC trying to heat it equally
Step 2 – using solder wick remove the excessive solder on the BGA pads, not everything will be removed
Step 3 – apply flux and repeat step 3 until make pads completely even with no solder blobs
Step 4 – clean with isopropile alcohol
Step 5 – apply tacky flux
Step 6 – position the BGA chip on the pads (in our designs we place 4 small pads in the BGA corners so when you place the IC the corner of the ICs lay on these registration pads)
Step 7 – heat the BGA with the hot air to 250 C and keep it hot above 250 C for about 30 seconds.
Lead Free Solder melting point is 225 C, to solder the IC reliable it should be heated to 250 C and then hold at this temperature for 30 seconds.
You can do some experiments to learn when the IC is heated to this temperature and how long it takes to heat up by using damaged BGA chip – put thermocouple on bottom of it and place the IC on damaged board as you have to measure the temperature of the balls not on top of the IC then start heating and monitor the temperature, you will see after what time, when you move the hot air gun the temperature reach 250 C, note that the distance between the hot air gun and IC changes the temperature significant, also the complete IC should be heated and you have to move the hot air with circulating moves not to keep it at one spot only.
Once you do the measurements you will know what amount of time you have to heat the IC and at what distance and you can try with real chip.
When BGA balls melt down they “collapse” and the BGA sinks down a little bit, with the time you will get experience and will notice this collapse to be sure when the BGA balls are really soldered.
You can check your soldering results with magnifying glass looking at the BGA sides.
Here is the move which show above steps:
May 29, 2014 @ 18:24:31
Please bear with my limited knowledge on this, just curious, it looks like you just “glued” BGA to the board, (and even in your video, the logo of A20 turned 90 degrees before vs after). then how this BGA get wired to the board? should it be somewhere A20’s thin wires to connect to the board? Thanks.
May 31, 2014 @ 11:06:23
What about PCB preheating? My experience shows it is worth to apply hot iron from bottom.
Other way some joints would be broken during coolling down.
Jun 03, 2014 @ 03:10:00
Does this create a reliable connection?
Do you need solder paste to solder a BGA? From the ones I’ve tried without paste, initially the device didn’t solder to the board, but the flux would just glue it down.
Does it depend on the balls themselves? Fairchild have BGA packages with balls that melt over 300 deg C and for those solder paste is a must.
How have you found it with the A20?
I’m still confused on whether BGAs need solder paste or not 😦
Jun 03, 2014 @ 09:36:27
BGA balls are made of solder, so generally it do not require additional paste, or if it require it’s just a bit of paste more because the flux in the paste is used, this is how BGAs are soldered in production
using just flux for repair is total ok, it should be tacky flux which to hold the BGA on place
it’s the first time I hear for BGAs with balls which melt at 300 it must be some odd part for high temperature apps, it’s bad idea to use solder paste in this case unless the solder paste is also with high melting temperature as if you use low temp paste it will melt but will not make reliable connection to BGA balls which are not melt, to have reliable joint the BGA balls must melt down and collapse otherwise you may have so called pillow effect (google search to see what is it)
Jun 03, 2014 @ 09:41:21
I’ve tried doing some TPS63010 parts in their 20 pin BGA and had no luck using flux alone. It might have been poor thermal control or my lack of knowledge.
Click to access AN-7001.pdf
Here fairchild specifically recommend using “regular” to make the contact, and the bga ball is used to maintain a constant height.
Sep 02, 2014 @ 12:26:29
For soldering bga chip to new PCB, shall I put solder first onto the pad or directly solder the chip with heat gun ?
thanks
Sep 02, 2014 @ 16:14:15
no need to apply solder to the pad, just flux
Sep 02, 2014 @ 12:26:59
Do I need a solder ?
Sep 02, 2014 @ 16:14:23
no
Sep 02, 2014 @ 16:53:13
do you mean flux (just grease ) or flux (mix with alloy ?
thanks
Dec 12, 2016 @ 22:50:15
How to check if all pins are soldered well?
Feb 20, 2017 @ 08:55:33
Awesome men! It looks impressive. This is my first time with BGA chips soldering and I have no doubt. The article is highly organised and with very informative video. Big thanks for sharing this with us.
Feb 20, 2017 @ 20:09:52
Hello, I have a question, could you help me?
I have a board that uses H3 allwinner, it is damaged, if I replace this H3 processor with a new one, would it be necessary to program new h3 with some kind of firmware, or only would a replace work?
I have seen that you made some boards using the H3, and also on your site you sell all new h3, I am worried about running after the exchange, I will be grateful with your help on this my doubt, thank you!
Sorry my English is not my native language.
Feb 24, 2017 @ 04:15:53
Excellent knowledge about the show, thanks
Jul 11, 2017 @ 17:05:09
Nice post with video tutorial. The replacement and the soldering of BGA chips is not so complex task but earlier I think it was too difficult. Thanks for sharing the post really helpful.
Aug 19, 2017 @ 16:13:55
Very impressive video tutorial OLIMEX Ltd. It’s very difficult to repair/replace BGA chips. it’s not everyone’s cup of tea.
Oct 06, 2017 @ 13:27:08
Thank you for explaining this process…
But u misplaced the chip in a different way than it was…
So does it mean that all chips have a universal pin structure and can be replaced by chips of other brands?
Jul 06, 2018 @ 18:45:08
How do you keep bubbles from forming under the green coating on the top of the chip? I have found this ruins the chip. Is it humidity causing the bubbles?
Feb 20, 2019 @ 11:09:31
Great video and thanks for sharing!
This video has cleared to me some important steps (as the use of a tacky flux to help the alignment).
Just a marginal question. You have soldered the new BGA 90 degrees rotated.
So it means or the first chip was misaligned or the new one was misaligned, and in this last case this video is only a demo and not a real repair (but in any case it was a very informative example).
Best regards.
Feb 20, 2019 @ 11:11:39
it’s tutorial, done on board which do not works, so just to visualize replacement steps, not real repair.
May 27, 2020 @ 13:23:05
The guidance here made me think again to learn more details of PCB soldering. Thanks.