This installation documentation is an alternate for the Intermountain F3A/B, F7A/B, and F9A/B. This installation uses the IMF4 decoder, and was performed by TCS.
NOTE: This installation should only be used if your model does not include wires from the motor. TCS recommends installing these wires for best results. For an overview of the installation process, click HERE
The upper three pictures show the Intermountain F7A with its shell on prior to the TCS IMF4 decoder installation.
Be careful as you take off the shell because it is difficult to remove and can be broken easily.
Here is a picture of the chassis with its shell removed where you can see the original Intermountain light board.
Gently, desolder both wires (green and yellow) of the original LED.
Using a phillips screw driver remove two screws (marked in red) that hold the board and chassis together. Those two srews supply the track power to the board.
Remove the original light board as shown in the picture above.
With the unit reassembled, place a strip of Kapton tape covering the chassis as shown. This will insulate the frame from the new motherboard. In some cases, excess solder from the motor wires will flow through the hole in the board creating a short. This tape will prevent this.
Install the TCS IMF4 decoder as shown above. Make sure the two power supplying screws are tight and fitted well so that they can supply the power to the board.
It is very important to have the LED wires soldered in the right direction - otherwise, the LED will not work. The upper copper tab connects to the green wire and the lower connects to the yellow.
Important Soldering Tip
Please do not use any flux either liquid or paste on the mother board. It will damage it. Use only Rosin core solder approved for electronics use.
We recommend to use only Kester "44" rosin core, SN63PB37, .015" diameter, part number 24-6337-0007.
This can be ordered from Techni-Tool under Techni-Tool part number 488SO157
Other solder tips
When stripping wire, only strip a tiny little bit of the insulation. Strip no more then a 1/64 of an inch. When the wire gets tinned with solder, the insulation will shrink back more. Try to not expose any more wire then half the length of the solder pad at most. In no case should solder or exposed wire wire ever be outside the boundary of the the solder pad you are attaching a wire to.
Click here for important information on properly Stripping and Tinning wire