Soldering

Placement of parts on the boards

Be aware that some parts need to be aligned in the right direction, e.g. all the ICs (more than 2 pins), diodes, LEDs and some capacitors (tantalum, electrolytic).

• LEDs: Have an anode (+) and kathode (-). The kathode is usually marked with a flat side on the larger diodes. The smaller LEDs have a little arrow (triangle) on them, with the kathode on the side to which the arrow points. The boards usually also have a matching arrow on them. Only the LED1-3 on the SB are a bit too small for that. Here, the kathode is towards the edge of the board.
• ICs: All ICs have a dot in one corner, indicating pin number 1. The boards, however, do not always point this pin out with a similar dot: Some instead show a half circle at one of the ends - ignore that one, and instead note that one side of the pin rows has a double line. Match this line with the side of the IC that is a little carved out.
• Tantalum Capacitors: The dash marks positive (+) side

Soldering

Take care when soldering this, if you are a beginner in soldering. Some very small SMD-Components have to be soldered:

We start assembling our flight-control first, heat your soldering iron up to about 300-350°C. SMD-Soldering is quite simple if you observe some rules:

1. Don't solder PB-Free if you are more or less beginner in this subject
2. Use special SMD flux or Colophony (optional, try it)
3. Don't start if you are in a bad mood or pressure of time
4. Don't solder ICs like the Atmel pin after pin. You may locally overheat it
5. Clean your PCB after soldering with a toothbrush and some Isopropanol alcohol (drugstore)

It can be helpful to print out the partlists, schematics and place.pdf as well as taking a high resolution picture of the unsoldered PCBs.

If you run into problems the following tips may be of help:

First parts should be some "easy" ones. Take some SMD-Capacitors or SMD-Resistors to get a feeling for the process. If you never did something like this have a look at the following movie: http://www.youtube.com/watch?v=FGr3GRQdZZc (the interesting part starts after "IC fixieren").

For better results without the need to remove extra solder, try "vertical drag soldering" by holding the PCB vertically.
See: http://www.youtube.com/watch?v=4V7tBPsECjc