Kernow / DJM teamed up to create a wonderful little model in the Adams O2, and cleverly designed will take DCC sound very easily - wires are provided for speaker,
routed from the boiler back to the bunker, where a SugarCube7 fits easily!
Our first approach uses a Zimo MX648 sound decoder, hard-wired in the boiler, removing the factory PCB with 6pin socket. There is a lot of space in the
boiler, so no problem getting this in there.
Our next approach retains the model's 6pin DCC socket, with a direct plug-in Zimo MX649N sound decoder. The length of space in the boiler is just about perfect! We
use a SugarCube7 again, as in the first approach, which pops in the bunker very easily.
Our final approach is also very simple, extending the approach in the 2nd example above - the MX649N 6pin diret plug-in again, but with the tiny SACC16
stay-alive connection kit, with a couple of 220uF/16V Tantalums on board. Again, this goes in quite easily - could even have used more Tantalums! In the bunker
we have increased the speaker size used to the standard SugarCube9. No modification required - just need to take the cab roof and back off, but there is plenty
of space in the bunker still.
Beautiful detail on the O2. Coal pops out revealing large space for a speaker, and speaker wires already provided. Boiler door is held on with small
magnets, so just pull it off and draw out the 6pin PCB.
The SACC16 PCB is tiny, with a flexible design that allows you to connect up to 5 Tantalums on board, or remove those parts of the PCB to shorten it. Any
16V capacitor including SuperCaps could be connected! We opt for a pair of 220uF/16V Tantalums on the top, to keep the height to a minimum.
Kapton tape around the SACC16 kit, we connect to the +VE and GND pads of the MX649N, then cover the decoder in Kapton tape too.
The model's PCB provides a pair of pads for the speaker wires from the decoder to be connected, so we do that, plug the decoder in and slot it
with the SACC16 into the boiler. There is actually plenty of space vertically. Length-ways, the decoder and 6pin socket board JUST go in perfectly!
The SugarCube9 speaker is connected the model's provided wires. With the cab roof off, and the cab back slotted out, access is simple, and we
fix the speaker into place using Black Tack. While the roof is off, add crew figures.
All back together...
On track, the little O2 runs well - the stay-alive making just enough difference to avoid stalling too often.