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Mount the circuit board firmly
The circuit board has to be built into the casing in such
a way that it cannot move during operation. To this end,
two small screws with nuts are used. Matching holes are
present in the circuit board and the cardboard housing. If
necessary, you can glue the two LEDs to the cardboard lid
with a few drops of all-purpose glue.
Carefully solder the components
Four push-buttons and two LEDs have to be soldered
to the pre-assembled circuit board. Make absolutely sure of
the position (correct side of the board and correct mounting
place) and the polarity of these components before solder-
ing. The push-buttons have to be soldered to the smooth
side of the circuit board (the one without SMD components).
How to do this is described in more detail below. The circuit
board has plated-through holes. Once the components are
soldered, it is very difficult to desolder them without caus-
ing damage, unless you use special tools.
