Do you have experience with surface mounted device replacement?

[orion456]

Hi,

I need to replace a surface mounted capacitor and a surface mounted 12v to 5v converter. The latter is soldered to the board both at 3 legs and at its back which is soldered to a heat sink.

Do you have experience removing such devices? Can it be done with a soldering iron or do I need a hot air station? How can I heat the 12v converter without also damaging traces?

The pic shows the converter and capacitor that need to be replaced. The left side of the converter is soldered to a metal heat sink.

Thanks

 

[don256us]

I bought a solder station that includes a hot air gun. I use that to heat up items like your converter. Using some tweezers or small needle nose pliers, once the solder is liquid, you can just lift it up. I then put a very small piece of cold solder on the pad and heat the area until it melts. Then I use the tweezers to place the new converter onto the pad in the proper place and remove the heat to let it cool.

Probably doesn't say what I think it says but should give you a starting point to look it up on youtube.

Edit: This is identical to the one I got. I did not vet to see if this is the best deal or a good seller. I only post it to show what I bought. It was based on recommendations from users here on the forums.

https://www.ebay.com/itm/862D-2in1-...=131713244885fb3671eb6a5843368b4ed5c982a51b30

 

[Dolk]

If you don't want to buy a hot air gun you can remove the bigger fet with a big soldering gun. My favorite way of getting off surface mounts is by just connecting all the leads with one big solder blob. If you heat all the points of the surface mount with one solder blob, it'll just slide off. This can be messy at times and sometimes grab other comoponents around it. I see that 0402 resister next to the output(?) of the part.

A regular soldering iron should take care of the rest of the parts. If you are working with the GND or a copper rich power plane, you can get a hair dryer to keep the section of the board warm. Place the hair dryer underneath where you are soldering and use the blob technique.

Once you remove the parts, clean up with solder wick and alcohol. Use ear cleaners with nail polish or similar to remove resin and other materials. This will clean the contacts which you can resolder the new parts.

Remember heat spreads, and when you heat up power planes typically there is a lot of copper. All that copper needs to be heated up along with the part you are working with. The lower the wattage your soldering iron, the higher difficulty you will have. Invest or borrow a good high watt soldering iron and you should be all set.