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Subject: 1905
The HO 1905 era modeler has more locomotives today than ever that can be backdated to that time period. The Bachmann "Russian" Decapod has the lines of the period. It would be perfect if it were a Consolidation with 57" drivers. It is a good substitute and can be backdated and the domes lowered to look more American.
I know there are sound versions available now but I had some Tsunami's left over and dual speakers improve the sound.

The first thing to do is remove the locking lugs from the connectors. They aren't needed and friction holds them together quite well.
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Note the position of the insulated wheels on the tender. Luckily I had a second tender when this fact came to mind. D-oh!!!. If they aren't right when the locomotive is assembled you will fry the decoder.
Checking the tender floor we could fit two 1.1" diameter speakers.
Speaker Selection
I have found that two speakers of different frequency ranges produce a more dynamic sound. I am using a Kobitone (Mouser #253-5011) with a 1.1" diameter with a frequency range of 550-6000 Hz and a Project Unlimited Speaker that is out of stock with a range of 600-20000 Hz and 1.1" diameter. Kobitone (Mouser #253-CE285-RO) is a speaker with at 220-20000 Hz and 1.1" diameter that has the frequency response listed wrong. I get mine from Mouser on the net. The same speakers will not give a better sound, dual differents will give more sound with less volume.
So you won't break the steps off the press the tender floor into a piece of soft balsa to locate the truck lugs. Drill holes to clear the lugs. I used 2 pieces 3/16" thick and long enough to clear the steps
Remove the brake gear from the bottom of the tender, it isn't glued. Press the frame into the soft balsa. This gives a solid base for drilling the sound holes.
Clear the tender floor of all the protrusions.
Drill and tap the truck lugs 4-40. If you have screws from an Atlas Controller they will screw right in with out tapping.
Glue the drill template to the tender floor with rubber cement.
The rear headlight bracket has to be trimmed to accommodate the speaker board.
Mark the hole centers.
Drill 3/64" diameter pilot holes.
Drill out the speaker holes. Buy new drills, it is easier to drill the plastic with sharp drills.
If you don't use a sharp drill there will be wander and the holes will siamese. Break those holes.
Click here to download our PDF drilling template
Make a speaker base from 1/32" thick balsa the same size as the template. Mark the speaker cutout centers.
Use a cheap school compass to scribe the cutout into the balsa. Several passes will put a groove in the balsa. Finish the cutting with a NEW blade.
Glue the speaker base to the tender floor.
Glue the speakers to the base with clear caulk. Spot the speakers with a couple of dabs. Let that dry and put a ring around the speaker edge.
I use two prong connectors for the speakers. Wire the speakers in series.
I took a picture of the wiring board to trace the circuitry. The page for the 8-pin connector from the Soundtraxx manual was printed out.
I printed the picture of the circuit board and traced the wiring and marked the wires from the locomotive connector.
A terminal strip was made from PC board. Divide it into seven segments. Solder the decoder to the strip and then the connector wires to the strip. The black wire should be far left.
Glue one of the weights to the tender body.
Widen the opening in the front of the tender body.
Drill holes into the tender floor for the truck wires. Solder wires to the truck pickups and and then to the terminal strip. The front truck is the black wire. Watch the wheel polarity, the front truck non-insulated wheels should be as shown.
Drill a 5/64" diameter hole through the coal load to make the tender body a Bass Reflex speaker configuration. The locomotive will sound better than the Bachmann one speaker configuration. With a little bit of re-tailing the 1900's era will have a great freight locomotive.
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