• Make sure you insert them with correct polarity (correct orientation); the negative end is denoted by a black stripe around the diode body. The silkscreen outline also shows a (white) stripe – this is the side the black stripe must lie. Note that the orientation is not the same for all diodes.
• Diodes are quite sensitive to heat. Thus try to minimize soldering time. The best approach is to first solder only one end of all diodes, then the other end – this gives them enough time to cool down in the time between.