VR T Class diesel decoder installation.

The decoder installation for the VR T Class was a little time consuming because once the body was removed I saw that fitting a Loksound decoder was I thought, not going to be too much of a hassle, until I had to wire up the speaker.

A non sound decoder could be an NCE D14SR that would plug into the DCC Ready plug, but the lights have to be changed. Another non NMRA 8 pin plug decoder like the NCE D13SR will be installed for the second non sound installation.

Remove all the handrails that attach to both the body and footplate.

Remove the body by holding upside down with thumb and index fingers, and push in while trying to separate the footplate.

The T Class has a DCC ready plug that is correctly wired BUT the loco has 1.5 volt lamps. These will have to be changed to 12 volt versions or LEDs.

Remove the light diode board and discard.

As the lamps have to be changed, this now means that it is not just a simple matter of fitting a “p & p” decoder to the plug. I generally remove the DCC Ready plug to make a neater installation.

Remove the capacitor by snipping it out with a sharp pair of small side cutters. Leave the red inductors.

Now getting the wires from the decoder to the speaker required complete dismantling of the T Class. Remove weight, bogies and motor to drill a hole through the thick footplate.

Mark a hole on the right hand side next to the motor mount.

Trim a little of the motor mount to allow the wiring to pass through a hole that will be as far towards the centre of the loco. This will allow the wires to clear the bogies and come out right at the fuel tank.

On removal of the diode light board, I found I had plenty of room to fit a Loksound sound decoder, but where to mount the speaker?

Wire up the decoder. For the power pickup wires I connect the two bogie pick up wires to a “trimmed” decoder wire in a sort of a “splice” with two wires on one side and one on the other, joined together. I fit a small piece of 1.0 mm heat shrink to the single wire and slide over the joint when soldered. This makes a really neat connection.

Motor connections: With the weight off I redid the lower motor connection with a small piece of wire instead of the “flat bar”. In the case of the sound installation due to the total dismantling, I removed the inductors. Along with the capacitor, these are not necessary with DCCC decoders, as the suppression is done inside the decoder. I soldered to the orange and grey wires to the motor connections.

Physically mount LEDs into the lamp “slots” and bending the “legs” that have heat shrink on them, to clear the front bogie. I had to renew the wiring to the front bogie and lights due the wire was damaged when dismantling.

Connect the blue decoder wire to the two 1,000 ohm resistors for the Prototype White LEDs from DCC Concepts and connect the associated wires to the LEDs.

The smallest Loksound rectangular speaker is a neat fit into the fuel tank.

Cut a rectangular hole in the fuel tank.

Secure the speaker into the fuel tank with Blu Tak. This also seals the speaker back.

Note: Only Loksound 100 ohm speakers can be used. 8 ohm speakers will damage the decoder permanently.

With the weight removed, cut a slot in the “rib” under the decoder to allow the speaker wires to pass down to the hole and on to the speaker. Shown in the second photo, I have secured these wires with the magic Blu Tak.

Solder the brown speaker wires to the speaker’s “pads” and route them out of the fuel tank, adjacent to the hole drilled in the footplate.

The plastic back of the fuel tank is now secured to the fuel tank with guess what – Blu Tak. This seals the speaker enclosure (fuel tank) to enable an air tight enclosure. This gives the loudest volume possible from a small speaker and low 1 watt of power decoder amplifier.

Secure the fuel tank to the footplate with the supplied screws, paying attention to the speaker wires so they don’t get crushed. Trim the box etc to get some clearance and tidy up with Blu Tak. Pull the brown wires through the hole and slot and secure.

Place loco on Program Track. Read a CV, example CV 1 to ensure all wiring is ok. Should come up with “3” for CV 1.

Operate loco on the layout if the “read” is ok.

When you are happy with everything, check all wires and make sure nothing will foul when the top is put on. It is all a tight squeeze, so double check.

Happy sound running.