Skip to main content

Fixing cracked solder balls under a BGA package

I got another pack of failed Xbox One controllers. Most of them had classic problems like broken LT frames,(which by the way I could not find anywhere) broken analog sticks and broken internal board-to-board connectors.
I noticed that one of these controllers was the strangest of all. Everything working fine with this controller except the LT and the Y axis of the left analog stick. I walked through my regular troubleshooting process and I didn't find anything unusual wrong. It discovered later that was a cracked solder ball under the main controller chip. The crack was probably caused by a strong external force like a drop or a bend.
As I continued repairing this poor gizmo, I realized if I pushed the IC to the board with my finger I get the right values on my tester and everything seems to work as it should. This ment that the cracked balls maybe fixable by a reflow so I reflowed the chip but it did not worked. I wanted to try to fix it by doing a reball, but I don't have proper equipments for that kind of process.
I saw a video made by a professional controller repair company that discussed these types of controller failures so I decided to try to implement the tips I saw in the video. I did not want to desolder the chip because I could not put it back. I needed to figure out how can I get as close as possible to the cracked balls so I carefully started to remove the epoxy body of the chip until I reached the cracked balls. Luckily the IC did not brake under the process.
I fixed the cracked balls, by using really fine wire. The balls were not reachable by the soldering iron tip itself, so with the wire, I could transfer the heat right to melt the cracked balls. 
I think I fixed this issue as cheaply and professionaly as I could and I took my soldering skill to the next level.
Here is some pictures of repair:
Cracked solder balls marked on another motherboard 
LT ball is exposed

Almost done 



WorkSpace

Comments

Post a Comment

Popular posts from this blog

JBC AD2950 Display Backlight Mod

I really like my JBC soldering station, perfect and robous tool. I usually just put the handpiece back to its holder, and after a few minute the station will activate the hibernation mode (no heating). This is a great feature because you don't have to turn on and off the station, but sometimes, for example when your 2 years old daughter start exploring your lab this can be dangerous. If you let the iron in hibernation mode, it is start heating very quickly (5 sec. from room temp.) as soon as you pull the handpiece out of its holder. Fortunately, my daughter dropped down the handpiece in time, and she don't get burned, but this was a terrible mistake as a dad because things could be happen much worse than in my case. The problem is when the soldering station is turned on, you don't get enough visual notification about it. The display are saying "hibernation" of course, but if you tired or you are in hurry, you probably miss it, and you will forget to turn it off....
2 comments
Read more

Razer GreenSwich issue in BlackWidow keyboard

Recently, I got a used Razer BLACKWIDOW Ultimate 2014 mechanical keyboard with the fancy Razer greenswitches inside. The keyboard looks awesome and I really like the illuminated keys too. I'm not a person who likes the lound, clicking sounds that this switches are make when you press them down but I decided to give it a try. Sadly, the smile in my face went away as soon as I plugged the keyboard in and started typing on it. Every second or third character was doubled or missed on the screen of my computer. Something was wrong for sure with the keys, this issue is called scattering by the way. Actually I know that before I bought the keyboard and this is why I was bought it. There was nothing left, time to investigate the source of this issue. After a few phillips head screws I got inside the keyboard, and I desoldered some of the failed switches. The switch itself was easily disassemblable, 2 securing on each side. The problem was obvious after I looked inside the switch, corrod...
Post a Comment
Read more

Journey with AllWinner A31 SoC a.k.a. born to die

!!!Allwinner A31!!! Quad-Core 64 Bit ultra cheap SoC for everyone!! Yeah sound good...but the truth are awful is some case . First of all do you know about the Banana Pi M2?The Banana Pi M1 (A20) was the killer of the first generation Raspberry pi . After the second generation Rpi was released the Bpi m2 was released too . But where is it ? The Bpi m2 was a huge fail (M3 was changed the M2 very soon) . Nobody care about the A31 SoC linux support . No community,no projects,hack or any interesting thing about this mini ARM board. And what about the android support? Little bit better but not in all case. My new target is a A31 SoC based tablet with nice screen and big battery . But something wrong because I can't turn on.And my journey started here. I took it apart and try to locating the wrong parts.I started on the power rails : Sorted Main Board WorkBench  APX221 is a dedicated Power Management Unit for A31 SoC. You can find a lot of informations  on sunxi linux...
Post a Comment
Read more