DPA4099 suddenly died within recording session. Input dual transistor labeled 3Ft was the culprit. Had to order it from Mouser. There are two types used throughout 1Ft and 3Ft, they are BC847/857 respectively.

I wouldn’t normally post about such a small repair but it was my first SMD repair. I recently acquired microscope and hot air station.


I need bit more practice but I hope it’s acceptable outcome. It works and that’s important.


For those new to SMD I learned few things.

  1. use loads of flux, more is better then not enough
  2. add leaded solder before removing the lead free, it makes things easier
  3. solder wick is your friend
  4. 340 degrees is enough
  5. kapton tape helps protect surrounding devices from displacing
  6. excess solder can easily be removed afterwards as long as there’s a plenty of flux