Kit: MX645PluX22; dual SugarCube24X15X7-2W; 17000uF SuperCap
Bachmann's 2020 re-release of their Class 20 diesel is very welcome, now sporting factory lighting and a PluX22 DCC decoder
socket (our favourite type for OO diesels!). It even comes with a SugarCube style speaker on board already.
Here you can see the speaker, which is inside the black box. It is just a 15x11mm component, so OK, but not particularly loud.
If you want to convert to sound simply, it is perfectly adequate.
Take off the blanking plate, and plug in the MX645Plux22 sound decoder. We have a special version of our Class 20 project,
which gives control of the various lighting features of the model.
We decide to improve the speaker, as there is just enough space to put in a dual SugarCube of 7mm depth. To remove the factory
speaker, we have to unscrew the PCB, which reveals a couple of screws underneath that hold the factory speaker box in place.
Our speaker wires are soldered directly to the contact pads on the model's PCB, then we secure it in place with some
double-sided sticky tape - we used this because it is ultra thin, so the speaker sits as low as possible.
Probably a bit overkill, but we love super-reliable running of our models, so we add in a 17000uF SuperCap for stay-alive.
Cover the SuperCap in Kapton tape to prevent it shorting with anything on the model's PCB.