As delivered, these units run off 12 VDC and switch that power on/off to a white wire. This power is turned on/off with the two buttons on either remote. On power up, the default condition is power off to this white wire. There are two changes we want to make to this operation. First, we want the default condition to be "power on" for our railroad. This makes it more convenient and provides for a "fail safe" condition, i.e. if it fails it won't prevent you from running trains.

Second, we want to switch track power on/off, not the 12 volts that powers the receiver. Upon opening the receiver unit I found that both these changes could be made in a few minutes with no additional parts.

Before we get started making the changes, there are a few things to cover. You need 12 volts DC from somewhere to power the receiver. Options are: possible accessory port on your track power supply, a 9 or 12 volt battery, a separate 12 volt DC "wall wart" (these are also available from All Electronics - part numbers change frequently just do a search). I happen to already have a "wall wart" unit providing 12 VDC to my railroad for sound units and other electronics around my Mystic Mountain Railroad.

The relay in the receiver has contacts rated at 15 amps. If your train power supply puts out more than this under short-circuit conditions, or if you want to shut off more than one power source to your trains, you can just add a more powerful 12 volt relay outside. In this case you don't need to make any changes to the receiver. If you have a single supply of 15 amps or less, read on.

Receiver insides with transmitter

Receiver changes

If your soldering iron is hot, and you have a 2' piece of wire and a Dremel handy, you can do this in 5 minutes. Open the receiver box by removing two screws, and gently pull out the circuit board. There are two (redundant) black ground wires. Cut one off, pull it out of the black sleeving, and feed a new (recommend at least 2' long) piece of wire through the sleeving. This will carry your track power, so use #18 or larger.

Turn over the circuit board and use a Dremel to cut a path through the copper/soldered traces as shown below. Brush the fine copper dust off the board with an old toothbrush or equivalent. Use an ohmmeter to make sure you've cut completely through and around the traces.

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Receiver modifications

The first change (in Red) separates the moving contact on the relay from the 12 VDC power for the receiver and adds the new wire to it which will connect to your track power supply. The second change (in Black) connects the white wire to the normally closed contact on the relay instead of the normally open one. This white wire will connect to your track.

Re-assemble the circuit board into its box and wire into your track wiring as shown below. The blue wire on the receiver is the antenna, so route this wire to an unobstructed place, away from metal, and as straight and as high as possible. I mounted mine with Velcro next to a window in my train shed. Note: you don't want to try to "steal" 12 volts for the receiver from your track power since, if the tracks short out, the receiver will no longer work.

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Wiring receiver to disable track power

Note: since we're using a relay to shut off power, we don't care what kind of power you are using, pure DC, pulse power, even DCC. It doesn't matter which of the two wires to your track you break to connect this.

Receiver mounted next to window in train shed

Transmitter changes

To open the transmitter, remove the screw on backside, pry open, and slide off the back; you don't need to remove the wire loop holding the two halves together. Pick up the rubber buttons and reverse them (rotate 180 degrees). There's no pins to hold them, but once reassembled they'll be held in place. Now the "on" and "off" on the buttons will be correct - because of the changes you made to the receiver relay wiring above.

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While it's open, check the battery voltage - mine were OK, but there have been reports of weak batteries which reduce the range. It's a 12 volt, type "27A" battery, if you need to replace it. Reassembly is a little tricky since there's nothing to keep the buttons or the circuit board from falling out until the case is closed. Once closed, everything is held securely in place.

Transmitter inside before reversing rubber buttons on right

Now when I operate trains I clip a transmitter to my belt loop and walk around my layout. If there's a derailment, I can quickly shut off the track power, re-rail the train, and turn power back on without having to race over to where my power supply is (inside the train shed).

These units have 256 "channels" like your garage door opener, so multiple units can be made (and probably already are) independent of each other. If you put your imagination to work, you can find a lot of other uses for these nifty units. Like controlling a sound effects unit. Or throwing a key turnout. The receiver board is small enough to mount inside an engine and control sound effects, lights, or ??? Anybody game to hook up a small solenoid to uncouple a train? Have fun.

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