At first, the boards
looked perfectly fine. But, after a closer inspection I spotted the problem.
The circuit used one surface mounted power diode and a number of tantalum
As shown below the
power diode and one of the tantalum capacitors looked very much alike.
Both had about the same size and both had a painted strip on the body of the
part. The assembly company had someone who managed to get the two mixed
up. The diode was soldered in the capacitorís spot and the capacitor was
mounted where the diode was supposed to go. Fortunately, the error did no harm
to any of the other components on the board. The boards were shipped back
to the assembly house for retrofitting.