Kit: MX649N; SugarCube5; SACC16 + 2x 470uF Flat Tantalums
Some quite impressive detailing on this model from Arnold, and the lighting is excellent too with working table lamps. Of
course, that complexity can make it harder to add DCC Sound, so some creativity required on this one...
The model provides a 6pin DCC socket, and DCC control of the cab light. The end lights and table lamps run directly from the
track, so no DCC control there unless we did some major rewiring - it is all rather intricate, so we decide to just stick with
the provided electronics.
As supplied to us, the customer had already removed the 6pin socket from the model, so we elect to solder the pins of the
MX649N decoder direct to the connection points on the PCB where the socket had been. Without having seen the socket ourselves,
it is difficult to know for sure if this was necessary, or if the decoder could have plugged directly in.
This soldering requires great care to ensure the pins are kept straight and do not contact each other.
There is absolutely nowhere inside the body for a speaker, so we have to get creative, deciding on a low-profile SugarCube
speaker under the frame centre. This will require some milling later, but for now, we fit some thin purple decoder wire in the
route that we intend to use. Small holes are drilled just beyong the end of the table lamp PCB, but just shy of the bogies, so
it all routes nicely without any fouling.
Our stay-alive is a cut SACC16 PCB with a pair of flat 470uF Tantalums. We'll hang it under the decoder area, and above the
drive shaft, so it has to be low-profile. We wrap the stay-alive klit in Kapton tape, and secure underneath, ensure it clears
the drive shaft completely.
We now mark out where the SugarCube5 speaker will sit, and using a milling machine we carefully remove enough space down the
centre for the speaker to sit. The edges of the under-frame equipment are kept and the speaker will be hidden behind them.
We bend the terminals of the speaker the opposite way and cut them short. This allows the speaker to sit more flush, and gives
neater access to solder the speaker wires on.
I'm not a huge fan of putting speakers underneath frames, as the magnets can pick debris up, but we have no option on this
model. However, we can reduce the risk by putting the plastic side down, which of course means we have to be especially careful
that the speaker's metal side does not contact the metal frame/chassis. For this, a layer of electrical tape and some
double-sided tape should work. A small dab of SuperGlue is applied to all layers to ensure that it won't fall off later.
Speaker in place now, with generous electrical tape to be absolutely sure of no shorts...
Paint the speaker enclosure and wires black to disguise.
Back together and running/sounding lovely! Certainly not an install for a beginner, but shows that it can be done.