Heljan O Gauge Class 42 Warship

Kit: MS950/LOK950P; YLR302815 and YLR603010 speakers

Heljan's retooled Warship has smaller motors and flywheels than their previous edition, and better lighting. Here we convert to DCC sound using an MS sound kit.

4 screws removed and the body lifts off. Unplug the fan from its' socket and we are ready to start the conversion. The model has a screw-terminal board which must be removed in order to convert to DCC. Wiring colours are a little mixed, but the terminals are marked so we can transfer methodically.

Below we see the Zimo MS950 decoder with plug-in adapter board (LOK950P). This adapter has solder pads for connection to the model's wiring. There is a screw terminal version of this board, but it is slightly longer, so we opt for the solder pad edition.

Terminal by terminal we unscrew the wires and connect up a wire, using DCC colouring standards, such as blue for comon positive. Motor and track are transferred using orange, grey, black and red wires.

The model has headcode lights, red tails and cab lights, but the cab lights are wired into the headcodes. We split these off so that we can control the cab lights separately from the headcodes.

Now here's a lesson in Heljan's wiring colours... never trust them! It turns out that the wires to the 'COM' terminal are in fact NOT all common positive! This doesn't matter when running in DC, but it certainly does when connecting to the decoder... one end is wired correctly for common positive, but the other end (headcodes and red) are switched around, so we have to test all the pairs to identify which is which, and collect the 4 common positive wires together! Not hard, but certainly a gotcha - thanks Heljan!

The LOK950P adapter is fixed into place with BlackTack, and offset to one side. The board and decoder are quite narrow, which is useful, as the fan control board needs to be positioned alongside it, rather than directly above - space for this is perfect.

Lighting is wired in, and the MS950 decoder plugged into the socket for testing. Our project is a modified one with the following connections:

• F0F: front headcode
• F0R: rear headcode
• FA1: front red
• FA2: rear red
• FA3: fan
• FA4: front cab
• FA5: rear cab

As mentioned, the fan control board must be moved across so that it sits alongside the decoder. Some BlackTack to hold it in its' new position.

Large scale models often work best with traditional-style box speakers... here are our potential choices... left-to-right, YLR453520, YLR603010 and YLR302815.

We tried with the biggest, the YLR453520, but couldn't quite get this in anywhere due to the fan units in the roof. However, a YLR302815 with its' lugs cut off slots perfectly in the void under the decoder shelf. Some BlackTack to secure it under there, with the speaker facing down.

For the 2nd speaker, we go with the low-profile YLR603010, which has excellent response and range. For this we build a plasticard shelf above the axle at one end, BlackTack'd into place. We could have fitted another one of these the same way at the other end, but the combination of 2 speakers works very well anyway.

Next we wire in the fan control unit between common positive and FA3 output. No dimming required, as the control unit takes care of this, though we do actually apply dimming anyway, as it is nice to have the fan run quite slowly.

Figures are #1 end, and all is done!

Please note that these guides are provided as useful resources for you, as-is. YouChoos cannot be held responsible for errors in the information, or for any damage caused to your models or equipment if you choose to follow any of the steps detailed here.