SMD repairs to FC's

Hey folks. So some of you have seen me around and I am sure I have rubbed elbows with most of you in one place or another. If you know me and have watched what I have been doing one thing has been at the forefront of all the stuff I have been doing. AlienWii brushed FC. Since laying my hands on this little gem of a brushed card around 10 months ago I have been led many places in search of knowledge. I won’t drag you all into those specific details because it is a sorted lot of things. About 3 months ago I started to practice my SMD soldering techniques with a specific goal in mind, learn to replace any of the SMD components found on these FC’s and other FC’s. I have successfully managed to revive the 4 cards that I was offered to help. One being mine and this is the video of that operation where I replaced the buck boost voltage regulator on that card. I am showing my amature skill in this performance but it was a success none the less.


Don’t belittle your skills Adam, you are doing a great job tackling the repair and resurrection of these priceless :alien:Wii FC’s. You and Benedikt’s FET replacement on a Micro MWC FC have inspired me to buy my first cheap hot air rework station and start to play catch up with you guys :slight_smile:

I agree with Peter, you’re doing good Adam. I like to secure the board for all steps when working with SMD components even when wicking the excess solder off of the pads after removing the damaged component so you’re not chasing the board around your work surface. I have a PanaVise that works very well for that purpose, helping hands like you’re using work well also. I assume you have your hot air station on the lowest air flow setting, otherwise the components will move on you. Good job, success is always gratifying! :grinning:

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I have a small vise that clamps to the table and need to implement that in the LAB here as that 3rd hand is ok but needs to be fixed if you are doing things like wicking solder like you say. I just finished replacing a FET on a card and and now working on a Gyro chip. Recorded the FET but am not recording this gyro chip as there is only so much time in the day. Actually, I will get the placement and soldering of the chip but have already removed the old and cleaned the pads.

I will have some new video up soon :wink:

Thanks Pete, I have 9750 more hours of practice to get my masters degree :wink:

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Here is another video of the buck boost chip being replaced on a PedroWii. Full uncut video. A little rough around the edges as usual but shows the complete procedure. This is how I do it and I am no expert, still pretty green at all of this but I have successfully replaced this buck boost chip on about 8 FC now. The buck boost chip is the #1 issue with the FC that do not have reverse polarity protection.

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Depending on the type of soldering task I find it easier to use the “tack one pad with solder, hold with tweezers, heat up pad to secure part” method over using solder paste. The only time I’ll really use solder paste and hot air station is if I have a QFP package or something of the like that doesn’t have leads. I had issues like you had with the part moving around too much.

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For sure this buck boost chip does not have leads and is a tiny little chip. 3mm x 3mm and there are 11 contacts for the chip. No tacking that to the board with solder let me tell you. All of the builds I have been doing with these open source FC have been the QFN package without the legs on the chips. I will be getting into the STM32 builds soon and those do have the legs.

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@madman1412 - understood. Yeah I believe it. I’m not a fan of those super small packages with no legs. I would say you are doing it in the best way possible then.

@Mullet yes chips with legs are easy, but these QFN No Pad chips are in a different league. There is no way known to man that you can tack them seeing as the pads are under the chip :smiley:

The three IC’s on these boards are all that package - The Atmega32u4, the buck boost voltage regulator and the MPU6050 gyro. It’s no cake walk let me tell you.

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