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USAT Quick & Dirty DCC install

The basic idea is to route the power from the track into the decoder, and then run the loco on the decoder motor output.

Typically, USAT locos have 2 "sets" of wires coming from EACH truck, and they use the familiar 2 pole "JST" style connector. The picture below shows on set from one truck, this one is an NW-2.

 IMPORTANT: you need to VERIFY what is said here with an ohmmeter. This will be part of the instructions, but do NOT be tempted to just follow the pictures!

First, we want to locate the connectors that have the track power pickup. USAT locos normally use more wires from the truck for power pickup.

Look at the upper connector in the picture above, there are 4 wires on the left side. That is the track pickup side. Separate this connector at each end of the loco.

Now you want to put a new connector and pigtail on the TWO connectors that go BACK to the trucks. Don't worry about the other 2 connectors.

Since the trucks are identical, you will now do something that seems strange, you have 4 loose wire ends, 2 from each connector you just attached. Twist the red of one to the black of the other.

You now have 2 wire sets, and each is 2 wires twisted together.

Now we need to determine which is the right (or engineer side) wheels and which is the left side.

Get out an ohmmeter, and test it to be sure it indicates 0 ohms when you touch the 2 probes together. Don't go further until you can test and see that it's working.

Now connect one probe (does not matter which one) to one of the wires, and then test ALL the wheels on one side of the loco.

One or the other side should respond. Be sure to double check ALL the wheels.

Once you have this tested, then connect the wire to your decoder. The engineer side is called the track + or red wire on the decoder. The firemans side is called track - or the black wire on the decoder.

Test the other wire to be sure it is connected to all the wheels on the other side of the loco, and connect it to the decoder, on the other track pickup input on the decoder.

At this time you have connected the track pickups to the decoder, both front and rear truck.

Now we are going to feed the decoder output to the entire loco.

Take another JST and plug it into EITHER of the 2 remaining "loose" connectors, and connect the 2 wires from that connector into the MOTOR + and the MOTOR - leads, these are the orange and gray wires. You have a 50% chance of getting it right, just hook up the wires.

Now the loco should run on DCC.

If the loco runs backwards, then remove that connector that goes to the original USAT circuit board and plug it into the other "free" connector. (again since the motor blocks