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Bachmann J-Class #611

norfolk & western j-class 4-8-4 #611

DCC Sound Decoder Installation Instructions


Having stood right next to the #611 under steam in Adrian, MI during an excursion in the early 1990s, and having paced it on I-94 eastbound past Metro Airport running effortlessly about 60mph, this beautiful locomotive is just one of those "must-haves."  So I bought the Bachmann Spectrum model (second-run), along with a Soundtraxx Econami Eco-100 Steam/Sound Decoder and a Soundtraxx 15mm round mini-speaker. I had never done a hard-wire decoder installation before, but with the help of the Internet (photos to guide the process) it turned out very nicely. My notes are provided below in the hope they prove helpful for anyone else who wants to tackle the job. This was a very satisfying project: my #611 runs and sounds awesome!

Disassembly Tip

Detach the tender loosely from the locomotive by removing the plastic sleeve from the tender’s drawbar post, then slide the tender off of the drawbar. At this point the locomotive will still be attached to the tender by a wiring harness. Remove the tender body shell from the chassis (remove two screws from the bottom, then gently lift shell upward), and you will see a six-pin wiring harness at the front end of the tender. Gently slide the six-pin connector back toward the locomotive until it is free of the circuit board. Carefully slide the connector back out through the rectangular opening at the lower front end of the tender. You will now be able to handle the tender chassis and circuit board independently. The circuit board can be removed to access the speaker mounting area on the floor of the tender chassis. The speaker mounting area consists of a pre-molded cradle with a downward facing speaker grill. See below for details:


Speaker Install

The baffle kit proved to be too large for the available space in the tender. However, the 15mm speaker fit perfectly in the pre-molded cradle/grill that is built into the floor of the tender. To access the cradle, you must remove the retaining screw in the factory circuit board. Place the speaker face down in the cradle and route the speaker wires toward the front of the tender. Place a 15mm square piece of packing foam (1/8” thickness) over the top of the speaker magnet and then replace the circuit board and fasten the retainer screw. The packing foam will act as a lightweight cushion that serves two purposes: 1) it insulates the speaker magnet from the circuit board, and 2) it helps create gentle compression between the circuit board and the speaker magnet  that secures the speaker against the bottom of the cradle/grill. The tender body serves as an excellent speaker enclosure and the sound is awesome.


Capacitor Install

Once the speaker is in place and the circuit board is re-installed, cut the blue (common) and green/yellow (ground) wires from the decoder in half. Discard the cut green/yellow piece, then twist and solder one end of the cut blue wire with the shortened end of the blue wire coming out of the decoder, making this into one double-wire “tail.”  Solder the other end of the cut blue wire to the positive lead of the capacitor. Solder the trimmed green/yellow (ground) wire from the decoder to the negative lead of the capacitor. Using double-sided tape, attach the capacitor to the underside of the coal load in the tender. Solder the double-wire “tail” of the blue wire to the far right #7 solder pad on the tender’s circuit board.


Decoder Install

Once the capacitor is installed, use double-sided tape to attach the decoder diagonally and flat to the underside of the rear deck of the tender. Looking at the interior of the tender shell upside-down, the left front side of the decoder (8 output wires) should be tucked to the bottom left of the long screw-mounting lug in the center of the tender. The right back side of the decoder (four output wires) should be oriented toward the top right back corner of the upside-down tender deck. Follow the table on the Bachmann parts diagram and solder the wires according to the directions. Once all the decoder wires are soldered in place, re-attach the six-pin wiring harness from the locomotive, then flip the tender shell back over and onto the chassis.  The diagonal placement of the decoder on the underside of the rear deck of the tender will ensure that there is no interference with the tender’s back-up light assembly.



I left the factory capacitors in place and observed that the starting speed of the locomotive was a little high. However, I adjusted from 28 speed steps to 128 speed steps and then the starting speed was very realistic. The chuff rate and some of the volume levels needed adjustment, but SoundTraxx has provided a great set of CV guidelines, so that went smoothly.  (back to main N&W page)  (link to Bachmann site)  (link to Soundtraxx site)

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