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I'll assume you know how to solder. Remember that this is not a raw beginner's
project.
3.3
Soldering the First Parts
RTC Crystal
Solder the low-lying parts first. Since we'll mount the resistors on edge, the
chip sockets look like the logical choice. Don't do that yet. We'll start with the
RTC clock crystal (Y2). This part is the size of a cooked grain of rice and is
hot-glued into a fold of heavy paper. Notice the rectangle extending from its
mounting holes. The crystal will lie parallel to the board in this area. Solder
the crystal into its holes leaving enough of the leads above board to let you bend
it down into the rectangle. Put a dab of epoxy or silicone RTV adhesive in that
rectangle and gently press the crystal into it. Let this cure before proceeding.
Chip Sockets
The sockets for U2, U3, and U4 appear to be of the press-fit variety. This isn't
a problem as long as you don't want to remove it after putting it in its holes.
Firmly, but gently press them into place and solder as usual. For the other
sockets, tape them down with some masking tape before flipping the board over
to solder them. If you're brave you can use a finger and tack-solder the corners.
3.4
Soldering Everything Else
Capacitors
Our next-tallest components are the capacitors. Remember that the tantalums
are polarized. A magnifying glass or loupe is strongly recommended to check
for the tiny "+" mark. Look at the rectangle silkscreened around each capac-
itor. The positive lead of a polarized capacitor goes in the tapered end of the
rectangle.
Resistor Packs
These are also polarized. Hold the part with the lettering facing up. There's a
dot on the leftmost pin. That's pin one and it goes in the pin surrounded by a
square.
14
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