Kit: MX645PluX22; YouChoos SugarCube12
The 2020 Bachmann Class 117 DMU model is virtually identical to the new Bubble Car 121/122 model - same PluX22 DCC interface,
on-board factory speaker and the same advanced lighting features.
In this example, we want to improve the volume level, as the factory speaker is not particularly loud.
Here is the PluX22 blanking plate, removed, then MX645PluX22 sound decoder inserted.
In order to gain access to the factory speaker, we have to remove the main PCB, as the speaker is underneath - it cannot be
accessed from the bottom of the model.
Here it is - a 15x11mm speaker component with spring clips upward to make contact with the pads on the board. Now we have
access to it, we can remove the speaker and its' box, and replace it with one of our SugarCube12 speakers - no bigger
physically, but gives a better sound, so is quite an easy solution.
An alternative speaker is our IceCube 18x13x10-1W, but this requires removal of the back and front walls of the undertray box,
as well as some careful enlarging of the aperture to insert the speaker up into (may need to lose one side screw fixing to do
it) - it does sound better, but with that little bit extra work... and the IceCube speaker has no spring clips, so you have to
solder some short wires to the model's PCB pads instead.