Farish Class 24 Diesel with Zimo MS sound and Stay-Alive

Kit: MS480, SugarCube6, 2x 470uF Flat Tantalums

A revisit to the Farish 24 with a view to fitting a Zimo MS sound decoder and a little stay-alive. The 24 differs from the 25 electrically in that it does not have LEDs on the original factory PCB, so the PCB can be entirely discarded, allowing for a few more options compared to the 25.

For this one, we have already added cab lights (mini white SMD LEDs).

Before we begin the butchery, we can test our MS480F (6pin on wired harness version), just hanging loose.

It may have been possible to get a SugarCurve6 under the roof by milling a little off the top of the chassis, but in this case we opt to mill into the fuel tank in order to install a SugarCube6 speaker. It is neater once done, but the milling needs to be done with care, including channels for the speaker wires to travel up to the top.

Once we are happy with the speaker installation, we can begin work on the decoder and lighting. Great care needs to be taken with the speaker so that nothing metal contacts anything in the chassis - A combination of Kapton tape, insulation tape and thin double-sided tape does the job, then the plastic chassis frame clips back over it providing the final security to hold the speaker in place.

The original PCB can be chopped to retain resistors for lighting (we need 2 for the directional lights, and another 2 for the cab lights). Original wires are removed from the lighting contact boards, and we add fresh new wires to these.

Shrink wrap is removed from the decoder and wires trimmed or replaced as necessary - if your solder skills are good enough, it is often better to replace the decoder wires altogether to avoid wire joins.

The screw holes from the original PCB are re-used to attach pickup wires, red and black.

Then the process of wiring up the lights (not shown here, though our first phase of connecting a pair of resistors to the common blue is shown).

We use the following outputs for lighting on the MS480: F0F - front headlights F0R - rear headlights FA1 - front reds FA2 - rear reds FA5 - front cab FA6 - rear cab

Unlike its' predecessory (the MX648), the MS480 has only logic-level outputs for FA3 and FA4, so we skip those and go for FA5 and FA6 for the cab lights which are full power outputs.

Not shown here, we have also added a pair of 470uF Flat Tantalum capacitors for stay-alive. These are joined in parallel and attached to the MS480's direct stay-alive connections (max 1000uF at 16V permitted that way). This gives enough to improve running and avoid too many stutters and stalls, so well-worth the effort (which isn't much!).

It proves a little tricky to get the lighting contacts sprung just right, but eventually we achieve successful contact 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.