TWB #57 | BGA Pad Repair Experiment

[@Derricky007]

The easiest way is to solder enameled 0.1mm copper wire. Only a steady hand and a nice microscope are needed. The best solution is to solder with lead free solder and adding leaded solder balls on the chip. Usual UV solder mask is absolutely fine for securing the traces. Sometimes it is pain in the ass to repair some traces. Rarely there are BGA sites where traces are in the second or the third board layer that are somehow connected under certain pads. Those are not visible and you can detect them by scraping off the epoxy glue residues that held the pad in place. For example a Macbook pro AMD site has such pads that are not visible by the bare eye, you can identify them just by taking a look at the board schematic.

[@effexon]

This is like treasure hunting :D

[@joek2029]

I give an A for effort. Although you're not using the right tools, you did a good job. Much better than a most of the DYI people out there including a lot of the repair shops across america.. lol. You touch on a few good points. You're right.. you dont know if the replacement pad or pads (in some cases) are going to move or lift during reflow of the chip. The correct way to do this is to connect the tail of the replacement pad to the circuit trace by micro laser welding. That process bonds the tail to the trace and is not able to separate under any heat conditions. Dont worry, hardly any repair shops use this method so don't feel left out. lol The machines cost from $8k to 10k for that ability. One tip I can give you is this, during the cleaning process (solder removal of the site) use a lot of flux and dab the solder braid (Don't slide it) onto each section of the solder pads.. if you slide it, you will damage and remove the mask that helps isolate each pad. If you did slide it and have removed some of the masking around the pads, you will need to use a think coat of epoxy to rebuild the missing masks around the pad. You will need to dry the epoxy with heat before you apply reflow flux onto the site.. re-mount the chip. This will help eliminate or resist any solder bridging during placement.. I can go on for hours.. been doing this for close to 20 years.. good luck.

[@ThatElectronicsFool]

Thank you for the advice! I try to do what I can with what I've got, and so far I've had a pretty good success rate doing various reballs, although this was quite the snag. In the end, turns out the chip was shorted internally when I did a bit more troubleshooting.

[@fwah23]

Sadly I'm finding this comment about dabbing vs sliding from already having destroyed the bga EC chip mounting pad from overenthusiastic sliding of solder wick, but nice to know there is a possible solution

[@kobi1ize]

What temperature can cause the solder pads damaging, and what temperature can't cause the solder pads damaging? I got the same issue when Im try to clean the pads from the solder with the soldering iron. Usually I used 350C but I think this is to hot! What do you think? I allways preheating the PCB from the bottom for 100C, but when Im clean the board somehow 1-2 sometimes 3 pads missing. I use the NC-559 flux but not to much.

[@pp3v42_g3h]

Do not use a soldering iron to clean the pads. Just move the iron above the pcb without touching the pads to remove part of the solder. Then use 320°C hot air, flux and a piece of soldering wick in a pair of tweezers to remove the remaining solder. This way the soldering mask and the pads stay where they should.

[@QuickishFM]

@@pp3v42_g3h yeah, true, i used soldering iron to clean some BGA pads a couple times and ended up ripping them straight off! Especially ground pads which sink the heat very quickly, my iron wasn't too powerful and the iron itself got stuck on the ground pad until a few seconds later it heated enough to let go. But i moved it too quickly and ended up ripping off the ground pad. The solder is a lot stronger than you think it is when starting out. It's best to use a hot air station (I use 400 C 80% airflow (~ 96L) ) flux and dragging a wick across, like you mention. I haven't damaged any pads this way. NorthridgeFix uses soldering tweezers to hold the wick but those tweezers are expensive.

[@rabindranathramsarop]

very good video would you say 5 minute epoxy can hold broken pads also?

[@ThatElectronicsFool]

It may hold them initially, but may not be able to stand the heat when soldering.

[@PiotrK2022]

@@ThatElectronicsFool Yup,epoxy melts at 200-300C, I believe, so it may not survive soldering...

[@GeertDroid]

I guess you use J-B Weld sku: 8265S Epoxy ? Can withstand 550°F or 287°C If not let us now. Thanks

[@shahsuleman7552]

You never moved the 2 pads which goes no where but inside the pcb itseld. Those 2 pad has no trace going nowhere. You just scratch those thats why you are missing that part of the vodeo.

[@gregh7457]

@ 16:29 did you say that with a straight face? didn't sound like it. You sure do like a challenge. I was watching some of Louis Rossman's video's a while back and the most entertaining ones are of him reballing, or should i say trying to reball, the apple pc gpu's

[@ThatElectronicsFool]

Controlling your balls is no laughing matter! Actually I didn't really plan for it to come out that way and I kinda realized what I said right after I said it. lol

[@vaio232]

Very good video, Im surprised you didn't complain, Louise has some issues lol I watched his vids but he also has alot info. Your info on replacing pads is very valuable.I was searching for just the right vid for it and u explained as much as you could. For me I'm a beginner learning along the way and of course I also lifted a pad. Very common issue on BGA boards. Thumbs up for taking a challenge most woundnt dare