Now, turn the board over and place C1, C2,
and C3 on the bottom side and solder. C7 also
goes on the bottom side. Lift it off the board
about 2-3 mms so you can solder L1. Note its
polarity and solder; refer to Figure 3.
Place L1 on the top of the board and solder.
■ FIGURE 3.
A complete kit to go with this article can be
purchased online from the Nuts & Volts
Webstore at www.nutsvolts.com
or call our order desk at 800-783-4624.
Using the four screws, attach the top and the bottom
of the chassis together. The screws will self tap and it will
make it easier for final assembly; secure the box for
Go to the article link and download the template.
When you cut out the template, glue it to the top and
sides of the box. The battery box should be on
the top. Drill the holes as marked and deburr
them as necessary. Hot water will remove the
Place the nine volt battery snap inside the
chassis (facing the bottom), and run it through
the slot on the right side. Run the battery wires
through the strain hole of the board and solder
the red wire to the + and the black wire to
the -. Solder the wires; refer to Figure 4.
Using two 3/8” standoffs, mount the board
to the top chassis using 1/2” 6-32 screws. The
holes in the board will self thread.
The end window of the LND 712 is very
thin and fragile, and is easy to poke a hole into.
(I speak from experience.) Strip a 4” piece of
#30 blue wire wrap on the short wire coming
from the side of the tube.
Solder a 4” #30 wire wrap red wire to the
end clip of the Geiger tube. Place a piece of
insulated tubing over the end clip to prevent
shock. Coil both the wires.
Mount the Geiger tube next to its hole
using a hot glue gun. Looking at the bottom of
the board, solder the red wire to the HV+ pad
and the blue wire to the IN pad.
Wire wrap a 4” red wire to the + post of
the speaker and a 4” blue wire to the other
post. Coil the wires. Glue the speaker to the
side of the box with hot glue. Solder the blue
wire to the round pad and the red wire to the
square pad on the ones marked SPK.
■ FIGURE 4.
March 2013 35