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SMD2 and Kato Unitrack Switch Machine Application Information |
Instructions for adding resistors to the SMD2: As discussed in the SMD2/SMD8 application information, the Kato unitrack electric turnout has two electrical connections as compared to three for other solenoid type switch machines. Since the SMD2 provides power on the common connection, two resistors are required to be connected from the common to power the machine. Figure 1 below shows how the resistors are electrically connected. These resistors can be physically located external to the SMD2 or can be soldered to the bottom of the SMD2 circuit board. |
The picture below shows the bottom
of the SMD2 circuit board. The resistors must be connected between the
Common
terminal and the Throw and Close terminal for each output. Notice the
arrows
pointing to the C, t and c labels on the board. These are the locations
where the resistors are soldered. |
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The picture below shows the resistors
soldered to the bottom of the SMD2 circuit board. The resistors used
are
22 ohm 1/2 watt (Radio Shack 271-1103 or equivalent). Use a piece of
electrical
tape to keep the resistor leads from shorting to other solder joints. |
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