Decoder Installs - Tsunami 2 ARM 38 Class

Adding Pickups, Lights, New Tender Chassis to the loco.

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This model of the 38 class is cheaper than the predecessors but has done more to get modellers actually modelling than any other loco. People are adding details and upgrading parts of the loco, adding sound and lights.

This page should give you some extra ideas as to what you can do an often how to do them.
Take the underframe from the tender, remove the two weights and fit them to the new chassis.
You also have to pull the the draw pin from the old frame and glue to the new frame. For the jobs that will never need to part - I use the glue shown - bought from Bunnings.

When you use this glue you will need a chain saw to get the parts seperated.
Drill four holes through the floor for the pick up wires.

If you have painted the new chassis, you will need to remove the paint as shown so you can glue the PCB to the crossbar for the phosphor bronze wipers - normally 12.5 thou for tenders.
This shows the wipers and the cable soldered to the PCB - red for the right rail and black for the left. The cable is swg 36 gauge.
This shows the pickups bent into position - theyrub on the back of the flanges and cause very little drag.
The cables are passed through the floor and are soldered to a short piece of PCB. The PCB most used here is a piece of PCB sleepter/tie - possibly left over from your turnout building!
Drill a small hole in each of the rear markers. The drill size is a #75. Use a pin vice here as a Dremel can make the hole too big or in the wrong place.
If you fit a lot of these marker lights the fiber optic can get expensive - I buy mine in bulk - this cost about $3.00 7 years ago and I still have some left.
The two fibers run through the tender into a small piece of styrene tube as shown. There is plenty of room in the tender. A hole is drilled cross ways in the tube so that the LED cab be inserted. The wires from the LED go to a small piece of PCB with a 1k0 resistor mounted on it.

All LEDs are SMD 0603 Warm White - they cost $5.00 for 500 with free postage. The resistors are 0805 size and just 1k0, the output of each function can be adjusted further with the CVs.
Testing the install with a 10 volt supply. I always test things at every step of installation - safer that way!
From the inside - the tube can be covered with a small piece if Gaffa tape - NEVER use masking tape or similar.
Now to the front end. Drill out the marker lamps as you did on the tender using a #75 drill. Also drill the headlight for its LED.
Now solder up some LEDs with Magnet wire. The wire comes in two colours as shown and is 4 thou thick. (0.004")

Thereare two tpes of connections shown here - the one on its own is called "ditch light" connection, the other two are "parallel" connection. This is used when gluing the LED to the back of a fiber optic as shown in the next photo.

For more information on how I work with the LEDs and some ideas on what you can do, go to another of my webpages
The top cable comes from the headlight and the two on the side are the marker lights. The fiber is passed through the hole, glued and trimmed off on the inside. Then the LED is glued to the fiber as shown.
Two pieces of suitably gapped PCB - the topone has the 1k0 resistor for the Headlight and the bottom one for the 2 marker lights in series with 5k1 resistor. Also shown are the colour coded cables going back to the cab.
The front of the weight has had 2.5 mm removed to allow plenty of room for the resistor boards on the inside of the smoke box cover. A piece of Gaffa tape has been put over the end of the weight for extra cover.
This is the complete chassis. The 8 pin connector and its bits have been removed. The 10mm Transducer has been mounted in its place, the volume for this loco is 100/255 and is plenty load enough.

The cables from the pickups, motor and transducer are shown coming back to the connector boards under the flywheel.

The lighting cables will be brough down the inside of the firebox and connected to another PCB next to the first one.
The decoder is mounted on the weight in the tender on double sided tape - ONLY use the black tape as the white tapes often have aluminium powder in them and they do not stick very well.

The wires here, going to the loco are all colour coded so are very easy to connect.