TM
APPLICATION NOTE
New Dimensions in Digital Sound Technology
Bachmann 2-6-6-2
Digital Sound Decoder Installation Notes
Overview
This application note describes the installation of a DSD-090LC Digital Sound Decoder into a Bachmann 2-6-6-2 Locomotive. All of
the components are installed inside the tender. No major mechanical modifications are needed and the entire installation should
only take a few hours.
A 1” speaker is installed under the coal load. The
sound decoder is wired to a standard 8-pin NMRA
connector and plugs into the “DCC ready” connector
in the tender.
Bill of Materials
Stock No.
Description
821102
810054
810119
810012
810037
810123
DSD-090LC Digital Sound Decoder
1” Speaker
1” Speaker Gasket (Pack of 4)
Two-pin Microconnector
Heat-Shrink Tubing
NMRA-type 8-Pin Header (pack of 4)
Tools You Will Need
■
■
■
■
■
■
■
■
■
Miniature Screwdriver Set
X-acto Knife with #11 Blade
1-1/2” x 3” x 0.040” Styrene Sheet
Flat Black Paint
RTV or Silicone Sealant
1/4” Drill
7/8” Forstner Bit or Spade Bit
Miniature Files
Wire Cutters
■
■
■
■
■
■
■
■
Wire Strippers
25W Solder Iron
Rosin Core Solder
Heat gun
Tweezers
Double-sided Foam Tape
Pin Vise or Electric Drill
#65 Drill Bit
Photo 1
Installation
1.
Remove the tender shell by unscrewing the small phillips head
screw on the bottom frame center, near the back of the front truck
(Photo 1). Set this screw aside. Slide the front of the tender shell
forward until you can slide the two tabs at the back of the tender
out of their slots.
2.
The coal load is a separate piece that can be removed by sliding a
knife blade under the back of the load and then gently prying the
plastic part loose (Photo 2).
3.
With your X-acto knife, cut out a piece of 0.040" sheet styrene that
measures 0.60" x 0.25". Paint this a flat black and glue over the
Photo 2
opening at the bottom of the coal bunker using
RTV. Photo 3 shows test-fitting the piece of
styrene before painting.
Gluing the template to the sheet styrene first
makes the measuring and cutting easier. Use
the spade bit to drill the large 7/8” hole (Photo
5). If you do not have access to a Forstner or
spade bit, you can drill several smaller holes
and trim the excess away with a hobby knife.
Photo 3
4.
Drill a 1/4" hole in the back of the coal bunker
for the speaker wires and connector. (Photo4)
Since this piece of plastic is simply glued in
place, it is a good idea to make a small pilot
hole first so as not to 'snag' the plastic. Drill
from the bottom of the tender shell to avoid
the screw boss.
Photo 5
Cut and trim the outer edges. Test fit the plate
in the tender. File the rear edge at a slight
angle to match the back of the bunker for a
perfect fit.
6.
Cut approximately 2.75" from each of the
purple wires on the DSD-090LC. This should
leave roughly an inch of wire still attached to
the decoder. Strip 1/8" of insulation from both
ends of the two 2.75" lengths of wire. Tin the
ends and set aside.
7.
Trim the leads of the 33 uF, 16V bipolar
capacitor to 1/2” (Photo 6).
Photo 4
5.
Create a speaker mounting plate from 0.040”
styrene using the template provided.
Photo 6
Speaker Plate - 0.040" Styrene
8.
1.46"
0.36"
0.66"
0.60"
Solder one of the 2.75” purple wires you cut
in Step 6 to one lead of the capacitor. Solder
the other capacitor lead to one of the speaker
terminals, putting a small piece of tape under
the connection to insulate it from the back of
the speaker.
1.32"
0.36"
0.88" Dia.
0.68"
0.11"
Photo 7
9.
Solder the other length of purple wire to the
other speaker terminal. Slide a piece of shrink
tubing over your connections and shrink with a
heat gun, being careful not to point directly at
the capacitor.
10. Solder one speaker wire to the solder terminal
of the male Microconnector (Photo 9). Solder
the other speaker wire to the remaining male
Microconnector terminal. Slide heat shrink
tubing over both connections and shrink with
the heat gun.
Photo 10
14. Strip and tin the remaining length of purple
wire still attached to the DSD-090LC. Slide a
piece of shrink tubing over each piece.
Photo 8
11. Peel the backing off of one side of the selfadhesive speaker gasket with a pair of tweezers.
Line up the gasket with the rim of the speaker
and press into place. Peel off the remaining
backing from the gasket. Line the speaker up
with the hole cut in the center of the speaker
plate and press into place with the speaker
terminals oriented toward the tab as shown in
Photo 9.
15. Solder of these purple wires to the solder
terminal of the female Microconnector. Solder
the purple speaker wire to the remaining
female Microconnector terminal. Slide the heat
shrink tubing over both connections and shrink
with the heat gun, being careful not the heat the
decoder itself.
16. Following the diagram below, solder the
remaining decoder wires to the 8-pin
connector. Since you will not be using either
the brown or yellow wires for this installation,
trim these wires back to about an inch and tape
the ends to the side of the DSD so they will not
short to anything.
Solder wires to ‘cup’ side
of 8-pin connector
Motor Right (Orange)
Rear Light (Yellow)
Not Used
Left Rail (Black)
Photo 9
12. Slide the two-pin speaker connector through
the hole in the coal bunker that you drilled in
Step 4.
13. Mount the speaker assembly in the coal
bunker as shown in Photo 10. Run a bead of
RTV around the edges of the mounting plate
being careful not to get any on the face of the
speaker. Set aside to let the RTV dry.
Right Rail (Red)
Function Common (Blue)
Headlight (White)
Motor Left Gray
NOTE: If you wish to use a cam to synchronize the
exhaust or use the DSD-090's lighting effects, do
not cut the yellow or brown wires! The yellow wire
can be used to hook up a tender backup light if
you wish; connect one buld lead to the yellow wire
and other to the Blue, or Funtion Common wire.
The brown wire connects to your cam.) Insulate
your connections.
17. Remove the dummy plug on the Bachmann
PCB and plug the 8-pin connector into the
exposed socket. The red wire should line up
with the 8 marked on the Bachmann PCB.
18. Mate the two-pin female connector on the
DSD-090 to the two-pin male connector
coming through the hole in the coal bunker.
15. Attach the DSD-090LC to the tender roof, on
the opposite side of the tender from the 8-pin
connector, with Velcro or foam tape (Photo11).
Photo 11
16. Before you reassemble the locomotive, inspect
your work for mis-wires, shorts, broken or
nicked wires.
17. Before replacing the coal load insert in the
top of the tender shell, drill some small holes
in the 'coal' with a #65 drill. Space your holes
approximately 1/4" apart and drill 30-80 holes
at random angles so they will not be visible.
Replace the coal load in the tender shell.
17. Replace the tender shell. Be careful that the
wires are not caught between the tender shell
and the frame. Replace the screw you removed
in step one. Complete the connection between
the locomotive and the tender by plugging in
the two small orange connectors.
17. CV Programming
Most of the sounds from the DSD-090LC will
not need to be changed. The default address is
3. You may wish to change the address of the
decoder by changing CV1 (see your command
station manual for instructions).
You may wish to make adjustments to the
Auto Exhaust Chuff Rate (if you have not
installed a cam). Auto-Exhaust automatically
generates an exhaust chuff rate proportional to
the throttle setting. Since every locomotive is
different, CV 116 is used to match up the Auto
Exhaust rate to the locomotive speed and may
be loaded with any value between 0 and 127.
Higher values will yield higher chuff rates for a
given throttle setting. A typical synchronization
rate may be computed as:
SPD
CV Value = 115.9 X ———
DIA
where SPD is the locomotive’s top speed in
scale miles-per-hour at full throttle and DIA is
the locomotive’s driver wheel diameter in scale
inches.
If you don’t know your locomotive’s top speed,
you can also estimate it and still get pretty
good results. A good rule of thumb is to use 45
MPH for freight locomotives and 70 MPH for
passenger engines.
Here are some suggestions for CV settings to
get you on track.
CV 2
CV 112
CV 116
CV 115
Start Voltage
Articulated Exhaust
Chuff Rate
Whistle Selection
20
129
34
1, 2 or 3
18. Put the locomotive and tender on the
programming track and check for shorts.
The LC Series Owner’s Manual Software
Release 2.00 is available for download at our
web site (www.soundtraxx.com/dcc/docs.
html). This manual will give you additional
information regarding CV set up and
customizing the decoder for your operations.