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This is the procedure used to install Dwarf
Turnout Signals on the Southern New England O Scale Modular Layout.
Any dwarf signal may be used, in this article we used Kiel Line two target
Dwarf Signals. T1 LED s are
used as bulbs for the signals simplifying the signal wiring. Simplified
wiring is a must for modular model railroads.
Build the dwarf signal according to manufacturers instructions. It is
important to make sure the LED will fit the opening by running a 1/8 inch
drill through the openings for the bulbs.
The LEDs required are T1 LEDs. The T1 LED is approximately 1/8 inch in diameter
and are polarity sensitive making them much easier to use in this application.
There are two leads on an LED the Anode
and Cathode (see Fig.1).
Fig. 1
Throughout the article we will keep referring to the
Anode and Cathode when soldering leads.
We will be using three different color LEDs green,
red, and yellow. Construct
the signals and test fit the LEDs in the signal. If they do not slide in
all the way you may have to remove the lip along the bottom edge of the
LED. This can be done by carefully chucking the LED in a lathe or the
chuck of an electric drill and file off the lip as it rotates in the
chuck.
The next step is to solder the wire leads to the LEDs. The wire used is a
30 Gauge solid wire available at Radio Shack. The wire is called Tie Wrap.
On the green LED cut the Cathode to approximately 1/8 inch and using a
small soldering iron (15 - 25 watts) solder the red wire to the cathode.
Then cut the anode to approximately 1/8 inch and
solder the white wire to the anode (see fig.2).
Fig.2
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On the red and yellow LEDs cut the anode to
approximately 1/8 inch and solder the red wire to the anode. Then cut
the Cathode and solder the white wire to the cathode (see Fig. 3).
Fig. 3
After the two leads have been soldered twist the them together.
You will need to drill a hole down through the base of the
signal for all four wires to pass through (see Fig.
4).
Fig. 4
(Rear View)
Install the LEDs as shown in Fig. 4 green in the top position and
red or yellow in the bottom position. Twist the two pairs of wires
together an pass them down through the base. You can now install the
rear cover of the signal.
You are now ready to install the signals on the layout. Because
the layout is built with 2 inch foam I used 1/8 inch diameter Plastruct
tubing imbedded in the foam to run the wires down through to the
underside of the layout. Drill a 1/8 inch hole to fit the tubing down
through the foam and the plywood supporting the foam. Cut the tubing so
it passes down through the foam and plywood. If the tubing is slightly
longer and protrudes below the plywood it will not interfere with
anything. Next mix some epoxy and place it around the hole for the
tubing. Run the signal’s wires down through the tubing and set the
signal in place making sure it is sitting correctly (see Fig. 5). Once
the epoxy is dry you may finish the scenery around the signal base.
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The last step is to wire the signals. On the SNEMRRC
Modular Layout an 18 volt center tap transformer is used to power the
Tortoise switch machines.
Fig. 5
This allows the use of a common wire for all Tortoise
switch machines throughout the layout (see Fig. 6 at bottom of page). Fig. 6 is a diagram
for a left hand turnout.
The common wire can be left connected to the Tortoise Switch
Machine. The wire from the control switch on the Control Panel is
disconnected from the switch machine and run through the signals as
diagrammed in Fig. 6. It is connected to the red lead on the signal
positioned and the point end of the switch and to the red lead of the
signal positioned on the straight end of the frog. On the signal
positioned at the curve end of the frog it is connected to the white
lead.
The remaining signal leads are connect to the remaining terminal
of the Tortoise Switch Machine.
Now apply power to the switch machine and the signals should
light. If any signal is lit incorrectly simply reverse the leads on that
signal and it should then be lit correctly.
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