Tuesday 28 August 2018

Octo 3 LED's

Tam Valley offer the own point selector with push buttons and LED indicators but what if you want to use your own dedicated panel.

TAM Notes:

The S pin goes high and low to five LEDs.  The middle pin is +5V and the B pin is ground.  You can use these to drive LEDs.

Here is the typical circuit, one LED will be lit at a time.

30T Class

The Wombat 30T is supplied with a small 6 wheel tender making sound installation a more difficult issue and this blog covers the installation of a Soundtraxx Econami UK decoder

The tender is secured with a series of molded clips on the floor that hold the body , remove shell using a fine blade or blade screwdriver. Exhibit care as the rear markers are secured to the tender back with a loom and plug.

With the shell removed unplug the markers at this point of the install - Place the tender to one side remembering there are some fine details attached to the coal bunker sides.

Tender shell removed

The first modification is to remove the factory plastic speaker base - this is mounted with small self tappers - remove and discard as it is not required. Its removal creates the room to allow reuse of the factory plug assembly and locomotive loom.

A piece of business card is cut to 34 x 14 mm and glued to the deck just to be sure, once this is done the original PCB is trimmed on the underside with a set of Xurons to remove as many of the spikes as possible and fixed to the cardboard with contact cement.

34 x 14 Insulator

Next we remove the two [2] factory switches - Note where the black wire from the switch is terminated - mark this and then remove the wire from the switch then solder the lead to the board bypassing the switch.

You can chose to do the same for the rear markers and these will be then on the headlight in reverse when the decoder is configured however we chose to allow independent control.

To do this remove both switches and the wire to the pad / decoder. 

Remove switches

Cut the overall length of the wires supplied to about 35 mm and solder to a 8 pin NMRA plug to the diagram opposite - there is not enough room for a full loom.

Solder the capacitor to the manufacturers detail. Connect the green/yellow to the negative and then using the surplus blue wire solder this to the blue on the plug and to the positive of the capacitor. 

Next split the wire and solder the positive [red] wire into the blue.

The brown wire for FX4 is connected to the black wire of the marker with a 1000 ohm 1/4 watt resistor.

Keep this small and tidy there is not a lot of spare space.

Installed Layout
Note the blue tack to secure the DCC hardware

The decoder and capacitor are secured on blue tack as shown above- it the only practical method.

The clear silicone is the point where the red from the markers spliced into the positive from the 8 pin plug to the capacitor positive.

Marker wiring

The final task is to solder the speaker to the wires supplied - these were run under the foot plate with the speaker to be installed in the roof or on the floor of the cab. The speaker shown is a 6 ohm edge port and if used avoid running at full volume to avoid the risk of amplifier damage.

To close this lot is like closing a suitcase before leaving to the airport. That plug got in the way and had to be bluetacked into the position shown to close the body - this is fiddly but possible.


Speaker ready for final assembly
Blue tack to the floor

Once tested and assembled we recommend that the tender and engine remain connected at all time except for servicing.

The decoder used is the Econami UK with the default shunt whistle. The air pump and dynamo are all there but not in the document and the basic CVs are supplied. 

We will install the plug and configure the decoder when purchased for a small additional charge - if you reset the decoder you will have to configure the CV list.

NOTE: Check all colours noted in this article against the manufactures document - where there is a error the manufacturers document is to be followed

The whistle on the 30T is closer to the one on the ESU Z27 but the ESU is a little soft for some - we are putting Heavy mode on all the time to boost the chuff all the other sounds are nice while not using a capacitor so is a little tider.

Soundtraxx does have a good chuff selection and strong sound and would be better on a exhibition layout.

Some of the engines will run in reverse to the selected direction - just swap the grey and orange wire - its the neatest fix - Paul Brooks

Speakers Wiring

There is a risk when adding dual speakers - wiring them in parallel and achieving a impedance [resistance] below the minimum recommended by the decoder manufacturer.

The impedianced is the tap or restrictor on a amplifier that prevent the amplifier from destroying itself so must be taken seriously.

Parallel wired speakers

The effect of wiring the speakers as shown above is to reduce the impedance from the recommended minimum of 4 ohms to just 2 ohms and was causing the amplifier to shut down. ESU are unique in using 4 ohms most other manufacturers are 8 ohms minimum so read the attached documents with the decoder.

Series wired speakers

The speakers must be wired in series to give a total of 8 ohms using two [2] 4 ohm ESU speakers. If two 8 ohms speakers were used these could be wired in parallel for a ESU decoder because the total resistance would be 4 ohms - OK for ESU but not most others.

If in doubt use the resistance measurement on the meter as shown above.