Installing the Tsunami decoder in the MMI K-28 is a straight forward and simple
process, probably 2-3 hours for the average modeler. I will be using all the original
lights and also the circuit board with the resistors for the class and number board
lights.
The first step is to remove the wiring harness (plug) from the decoder. You'll need
to remove about 1/8" of an inch of the purple shrink wrap. The K-28 already has
the wiring harness in place and this is what makes it a simple job.
Next I installed a 2" round speaker from Soundtraxx(#810056). These speakers give
you a deep bass sound and is the best speaker I have found. The speaker was mounted
to the tender floor with double-sided tape. I also soldered on the two pin micro
connectors from Miniatroncs (#50-001-02) to the speaker and back-up light. I used
the male connector on the speaker and the female connector on the back-up light.
This way there is no mixing them up when it comes time to connect them. Now drill
a hole in the tender floor behind the drawbar and off to one side. Make sure the
hole is big enough for the second connector to come through with the first wire
in place. You may also notice that niether of the connectors is long enough to reach
the hole, that's because the connectors coming from the loco will be long enough
to reach inside the tender. This will leave two pairs of wires between the loco
and tender and no possibility of binding on the connectors.
Remove the equalizer bar on the underside (front), it sits between the cylinders.
With that out of the way, remove the long screw that goes into the smokebox. Remove
the two screws under the cab. Once these are out the boiler should come off easily.
Disconnect the headlight and class lights/number board lights (2 connectors). Here
is a picture of the loco with the factory wiring:
Loosen or remove the retainer bar for the white plug. Lift the metal tab that is
holding the wires down underneath the motor, this will allow you to stretch out
the wires as needed. Pull the plug off to the engineer's side then tighten or replace
the retainer bar. Be sure the wires are running under the bar. Next, clip the blue
and yellow wires (back-up light) just behind the moter and attach the male micro
connector. Be sure it's long enough to reach into the tender. Be sure to clip the
wires back far enough so that when you put the shrink tubing on it doesn't stick
out from under the cab. If it does the shrink tubing will stiffen the wires and
could cause binding problems.
Next, add the female connector to the purple speaker wires. Once again, be sure
to get the splice under the cab so the shrink tubing doesn't cause problems.
Plug in the decoder to the wiring harness. If you are going to use the cam for the
exaust chuffs, you'll need to connect the brown wire to the cam socket. This is
easily accomplished by soldering on a Miniatronics(?) single pin connector to the
brown wire.
Socket for the cam wire:
Secure all the wires and position the decoder in front of the gear box. Don't forget
to make the connection to the cam.
Now its time to put the boiler back on. Start by plugging in the headlight and the
classlight/number board light. Be sure to get these connected properly. Also, as
a precaution, I cover the small board that contains the resistor for the lights
with some electrical tape. Get the boiler in place starting with the cab. As you
work the boiler back onto the frame, you'll need to position the decoder and resistor
board side by side into the boiler cavity. Once that's done, the boiler should come
all the way down onto the frame. Finish the boiler assembly by replacing all the
screws.
The last step is to make the connections in the tender by running the connectors
through the drilled hole. With the speaker and back-up light connected, replace
the tender shell.
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