This is the second part of my adventure of installing DCC in my brass K-27 2-8-2. The first part involved installing a four function decoder in the smoke box. This decoder controls the headlight, classification marker lights, cab light and firebox light.
The reason that I am using two decoders in my engine was to reduce the number of wires between the engine and tender. If I had used the Tsunami in the tender to control the lights, I would have eight wires running between the engine and tender, I was able to reduce that number down to four.
This is a link to the front decoder installation:
http://model-railroad-hobbyist.com/node/7655
Now on to the second part. I always like to keep my wires nice and neat. One of the methods that I use is to glue heat shrink tubing along the path that I want to wires to run. Then I thread the wires through the tubing like conduit.
The photo below shows how I secured the wires to keep them neat and away from moving parts.
Four wires are required on the running gear. The Orange and Gray wires enter the Engineers side and threaded up to power the motor. The Red wire enters on the Firemans side and is attached to the frame to pick up power from the driving wheels on the Engineers (right) side. The White wire also enters on the Firemans side and attaches to the sound cam on the front axle. This will control the chuff and keep it in sync with the rotation of the wheels.
The plugs that allow me to disconnect the wires from the tender were purchased from TCS. The little squares that hang down on either side of the draw bar in the picture below are the females the will accept the plugs that will come from the tender.
http://www.tcsdcc.com/public_html/Zen/index.php?main_page=product_info&cPath=45&products_id=288
I said that I only needed four wires between the engine and tender, but actually I need five. The fifth one comes from the front decoder. The front decoder picks up power from running gear frame, but it also needs a ground to the tender. If you look closely at the draw bar, you will see the fifth wire. I soldered it to the draw bar and the draw bar will attach to the tender to complete the ground for the front decoder.
The rear decoder, a Tsunami TSU-1000, will fit in the tender shell along with the speaker. In order to run the wires into the tender, I needed to drill holes on each side. These will be hidden once the tender shell is installed.
The next task was to assemble the speaker. This is a 23 mm high base speaker from Rail Master Hobbies with an enclosure.
http://www.railmasterhobbies.com/Speakers.htm
I first passed the two Purple speaker wires from the Tsunami though the back of the enclosure and soldered it to the speaker leads, and used Canopy Glue to glue the speaker face to enclosure. For some reason the speaker front had four holes, one in each corner. I plugged those holes by gluing round toothpicks in the holes and cutting them off flush after they dried.
I then used Decoder Pro to set up the TSU-1000 now that the speaker was attached. I used leads from my NCE to clip to the Red and Black wires on the decoder. Better to make sure everything works before things get glued in.
With the speaker assembled I need to attach it to the tender floor above the holes in the tender. Because the cone of the speaker needs to flex a little, it could not be glued flush to the deck. To solve this I used two sided foam tape (Scotch Indoor Mounting Squares, this is the stuff used to mount pictures inside frames). I cut the tape in very thin strips 1/32 wide and outlined the four sides of the speaker and attached it to the tender floor. This raised the speaker face about 1/32 from the deck. In the picture below, the speaker is below the bundle of wires.
The next task is to actually wire up the decoder. I laid out the color chart of wires.
The Orange and Gray wire that go to the motor were soldered to decoder, making sure that I covered all solder joints with shrink tubing.
The Red power wire was soldered to the decoder and then the White chuff wire was attached. The last wire was the Black ground wire from the decoder was soldered to a clean spot on the tender deck. This will complete the electrical path to the tender trucks.
I used a small square of foam tape to attach the TSU-1000 to the side of the speaker to hold it in place.
To keep the draw bar from shorting, I slipped some heat shrink tubing over it and used the soldering iron to shrink it down. This protected the ground wire from the front lighting decoder.
Here is a video of the K-27 going through its testing:
Well that is all for part two.
In part three I need to build plugs to allow wires in the boiler to attach to wires on the running gear. I want to use plugs which will make it easier to perform maintenance and detach the boiler at a later time.
I need to attach the tender shell, and use Decoder Pro to tune the Tsunami, then do a lot of testing.
Cheers Bill Beverly
