In my last post I told you about purchasing a couple of Blunami sound decoders and promised an installation article. In this post I'll show you how I put the decoder in a Bachmann 4-8-4 Northern and I'll show you a couple of different options during the installation. There are a lot of pictures, so fair warning, it may load slowly.
First, you are going to need a donor locomotive. I picked the Bachmann Northern because it has a huge 52' tender, and also because I have three of them laying around that I've been able to pick up for good prices, and they are all split-frame versions. However, not all split frame versions are created equal, as I will show you when it comes time to install the locomotive wiring harness.
Notice that I installed the two-pin connector that Richmond Controls includes in their kit. For the regular DC installation, the other side of this connector is fastened to the engine, which allows the tender to be unhooked from the engine. In this installation, I connected the other end to the decoder track power wires.
In my previous installation I mounted the speakers to the tender floor. In that configuration the decoder stays with the tender floor when the shell is removed, so the truck wires are connected directly to the decoder wires. In this installation I mounted the speakers in the tender shell, so the decoder will stay with the shell if it is removed, which is why I chose to use the two-pin plug to allow for the complete removal of the tender floor.
The TCS six-wire plug is also connected to the decoder and the connections are insulated. I used a liquid insulation, but heat shrink would work just as well (and be less messy). TCS provides these connectors in a flat 6 wire plug or in a 2x3 plug, and there is also a flat plug version with black wires (one has a white chaser so it will be connected properly). The black wire version might be better to disguise the connection, the colored wires definitely stand out.There is plenty of room in the Northern 52' tender shell for the decoder, even though it is intended for HO locomotives. There is plenty of room for the speakers in each end as well, and the entire thing fits right over the weights on the floor.Since I was using two speakers they had to be connected together. Soundtraxx cautions against using speakers less than 4 ohms, and each of these speakers are 8 ohms, so I wired them in series. Wiring in parallel would drop the impedance to 4 ohms, so that wasn't an option.
The decoder has plenty of wire for the speakers, so I cut some off to connect the speakers together.. I toyed around with several options when installing the speakers. I thought about mounting them on the forward and aft tender walls pointing inward, but I found there was plenty of room to install them on the top of the shell facing down. Later during testing I discovered that the sound was louder in that configuration than in the previous floor mounted installation.
The six wire plug feeds out of a slot cut in the front of the tender shell and the floor installs with no issues. The harness wiring was tucked underneath the decoder, so the only wiring I had to fight with was the wiring coming from the tender trucks. The screws on the trucks have to be left slightly loose so that the trucks will pivot, the Richmond Controls wipers interfere with the pivot action if the screws are too tight.
And with that done, it was on to installing the other side of the TCS harness on the locomotive.
Both of these locomotives are split frame versions, but as you can see the locomotive on the bottom has a couple of extra screws hiding under the trailing truck.They both run much better than the previous plastic framed version, but the one on the bottom runs slightly better than the one on the top. The biggest difference is in the motors.
As you can see, the top version has the old open sided motor that Bachmann has used for decades. The other version has a nice little can motor that is used on almost all of their newer locomotives tucked inside where it can't be seen. The bottom locomotive had to be completely disassembled to electrically isolate the motor and install the wiring harness, but because the brush caps are exposed on the top locomotive the wiring installation was much easier. The only part that had to be removed on the upper loco was the headlight, to connect the white and blue wires.
The bottom locomotive got holes drilled and tapped for 00-90 screws in each frame half so that brass tabs could be used to connect the track power wires to the locomotive. The Richmond Controls kit includes a neat little bit of double-sided PC board that can be inserted between the frame halves for the wires to be connected to, but I felt this would be a more secure connection.
For the top locomotive, the brass strips that connect the motor to the frame were pulled out of the motor brush covers and wrapped around the frame. The track power wires were then connected to them, and the motor wires were soldered onto the motor brush covers. Care must be taken not to overheat these brush covers, otherwise they may separate from the motor and destroy it. Ask me how I know...
Just a dot of solder on the brush holder is enough to secure the wire. Use of a non-corrosive rosin based flux intended for electronics work is a great help in getting the solder to flow quickly. Under no circumstances should an acid based flux be used! The track power wires are likewise soldered to the brass strips that were formerly connected to the motor brushes.
After the connections are made to the motor and frame a piece of thick styrene can be inserted between the top of the motor and the frame to prevent any inadvertent contact. I cut this piece and test-fitted it before connecting any of the wiring.
The head light holder is secured to the locomotive with a single screw under the leading truck, the same screw that holds the cylinders in place. The bulb holder has to be removed in order to connect the wires from the harness to the bulb.
On the bottom locomotive there was a capacitor installed with the headlight bulb, but on the top loco the bulb wiring was just wrapped around the holder. I opted for an LED on the bottom loco, but I simply soldered the wires directly to the bulb on the top one. There is plenty of room for an LED resistor in the space behind the curved bulb holder. The connections are insulated to prevent contact, and then the holder is reinstalled with its single screw.
There is a plastic piece that the shell screws into that has to be modified for the headlight wiring to pass around. The sides of the screw holder are trimmed back with a sharp hobby knife as shown in the next two photos and the wiring is routed around it, one on each side.
And with that the wiring is done. Reinstall the shell and connect the connector to the tender, paying attention to the color codes to ensure the connection is correct. Reattach the tender and put it on the track to program.
Using the Blunami app on your phone couldn't be easier. It can be used with either DC (turn the throttle knob all the way up!) or DCC power, and all the speed tables, lighting effects, and other CV's can be programmed either through the app or using your DCC system. You can run multiple locomotives in the app as well, in fact I found it easier to do so that way than on my NCE PowerCab system. I had both of my Blunami locomotives running via the app to speed match them and it was much easier than trying to do it on the Power Cab.
I must say I'm pretty impressed with these decoders, and I certainly hope that SoundTraxx can shrink the size of them in the future so they will fit into more N scale locomotives.