The Dapol N Gauge LNER A4... installation guide for DCC sound...
When removing the tender body, and uncoupling the drive-shaft from the loco, you'll need to also unscrew the 2 wiring screws
underneath the rear of the loco. Next, remove the 6-Pin DCC circuit board and carefully file down the mounting points where the
socket was attached - the aim being to make as much room as possible.
The pictures below show the completed installation using a CT SL76 wired decoder, 100uF/16V tantalum capacitor (the yellow
box), and a CT SugarCube speaker (with slightly reduced height enclosure). The 4-wheeled tender is long enough to stick the
capacitor behind the speaker at the very back.
It all goes in very neatly, with minimal wiring and everything taped down using electrical tape or thin double-sided tape.
The finished article, sounding loud, crisp, and running smoothly:
Here's another Dapol A4, "Silver King", with more detailed photographs...
Unscrew the pickup wires joining loco to tender, so you can separate them - this isn't strictly necessary, but it does make it
easier to handle the tender independently while you are fitting DCC sound:
Remove the 6pin DCC socket and circuit board, chop the pickup wires close to the board and remove the 2 plastic angled screw
mounts where the circuit board was fixed:
If the sugar-cube speaker and enclosure have been supplied to you unattached, and unreduced, you'll need to reduce the height
of the enclosure by a couple of mm to make the installation more comfortable. Don't worry though, sound quality and volume are
not affected hugely by doing this. See the photos below to get an idea of the reduction required on the enclousre - I've put an
unreduced enclosure next to the reduced one for comparison. I have used a thick double-sided sticky pad, cut in the shape of a
cross to fix the speaker to the tender chassis - it is cut this way to avoid touching the wheels:
If you purchased the decoder from YouChoos, you probably already have a tantalum capacitor pre-wired to the decoder. If not,
and you want to include a capacitor (recommended), then you'll have to add a wire to the GND solder pad of the decoder (shown
as the closest pad in the picture below). I've actually removed the white, yellow, green and purple wires altogether as they
are not needed in this install, and reused the purple wire for the capacitor's GND (negative) connection:
Next, attach some thin double-sided tape across the length of the speaker (note that the edges are not covered, to allow
sufficient air to move). On top of this is where the decoder will be seated. I've used enough double-sided tape to hang right
over the back of the speaker as this is where I plan to mount the tantalum capacitor:
On it goes... the SL76, with wires trimmed to more practical lengths. Be especially careful not to put unnecessary force on the
wires, because the SL76 is so small that it is quite fragile - it is easy to pull a wire off the decoder, or even a whole
solder pad - this is the price we pay for such miniaturistation:
Orange and grey direct to the motor terminals. Black and red to the pickups. Browns to the speaker terminals:
Common +VE blue to the capacitor's positive terminal, and the GND wire (purple in this case) to the capacitor's negative
terminal. Mount the capacitor on the back, tidy up the wires, and you're done! Remember to test it before you put the tender
body back on!