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Boulder Valley Models Twin Schnozzer Build-Update

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  • #16
    Well, nearly three years have passed, I have since added Tsunami sound to two of my Schnozzers. The one pictured above will be getting sound, and I will be finishing up a second unit of mine painted green. THREE Twin Schnozzers on the layout at's Schnozzer-Palooza!

    I will post a simple tutorial on the sound install, as I found a way to avoid overheating of the TSU-750 decoder and to use a much bigger speaker in the roof of the unit (rather than the .5 inch provision in the chassis). Stay tuned for developments.


    • #17

      Schnozzer-Palooza? Oh goodie! I've got my costume ready.

      Disclaimer: I make Schnozzer kits, so I could stand to profit if this thread creates a mad rush on those. However, with my clever new disguise ... and this is especially brilliantly clever because the fake nose and glasses look exactly like my real nose and glasses ... oh wait a minute ... [:-blindfold]


      Chambers Gas & Oil -- structure build

      Quality craftsmanship with a sense of humor! []


      • #18
        Nice going Verne....I will have to dust off my

        Schnozzer and follow along on the sound install

        tutorial...did you use LED or incandescent lights?

        Great paint job by the way....


        • #19
          Brilliant disguise indeed, Dallas!

          Thanks Geezer, I will show what's under the hood(s)...including the tiny incandescent bulbs I used. Call me a troglodyte if you want, but I like the warmth of incandescent lighting for headlights over the LEDs.

          Speaking of troglodytes... [^]

          I was poring through the Durante Motors files on the Twin Schnozzer, part of the collection of the Wiese N Heimer Hysterical Society, and found this image that provided the inspiration for the Twin Schnozzer:

          So, the original prototype came from the Andes, in a B+B, push-me-pull-you configuration. The two-way llamas were bred for the steep, narrow trails. If you inspect the photo closely, note the unusual pattern in the critter's coat:


          For comparison purposes, and I ain't sayin' anything here, just pointing out a similarity to two well-known model railroading suspects...messrs. Malcolm Furlow and Dallas Mallerich.

          Coincidence? YOU be the judge!


          • #20
            I can't tell whether I was wearing the real nose and glasses or the fake noses and glasses in that one!


            Chambers Gas & Oil -- structure build

            Quality craftsmanship with a sense of humor! []


            • #21
              Dallas would give Howie Mandel a run for the money!! LMAO!


              • #22

                OK, enough silliness, let's get busy.

                Here are the three Twin Schnozzers in their current state. For simplicity's sake, let's refer to them (left to right) as Larry, Moe and Curly. Larry and Moe need finishing touches on their DCC installations and final weathering, and Curly will receive a sound decoder and lights.

                Wanna drag? Here are the critters all together in the San Lorenzo yard.

                Here is Moe, equipped with a Soundtraxx decoder, headlights and link and pin couplers. I left the coupler lift bars in place; I may decide to return the EZ-Mate couplers.

                Here's the frame with the body removed...pretty straightforward. You can see the underside of the brass heat sink that supports the decoder. This is an important element of this install, my original attempts to install the decoder against a cab wall all led to decoder overheating problems. The resin walls just don't absorb enough heat, but the brass heat sink works perfectly.

                Nestled among the air tanks on the underside of the frame is a space to install a small speaker facing down towards the tracks. I originally tried that solution, but the sound lacked the presence of my larger locos. So I went with the solution pictured here, a 1" speaker with a baffle in the roof. This provides excellent sound through the open windows in the cab. (I still have to figure out how to hide the wires.)

                Here's the decoder, capacitor and headlight wiring. I chose tiny 1.5 volt headlights instead of LEDs. Call me old fashioned, but I much prefer the warm, bright glow of the incandescent bulb to an LED, and they look like headlight bulbs when not turned on (instead of little plastic squares in the headlight housing).

                I am going to start with installing the decoder in Curly, and then put the finishing touches on Larry and Moe. More to come!



                • #23
                  they look great verne. nice and crusty will the green one go the same way?

                  did you widen the deck by any chance?


                  • #24
                    Thanks, Andy. Larry, the green Schnozzer, will not be heavily weathered and will appear in pretty good condition. The trio all have wider styrene deck overlays with I-beams along each sill for give the loco a wider look.

                    The first step is to remove the three screws holding the circuit board to the frame. The small PC board at the top left is the headlight, we will remove this. We also need to remove the decoder side of the board, as it will be replaced by a Tsunami TSU-750. The arrows show where the board should be carefully trimmed to remove the decoder.

                    Note the soldering pads (the row of larger holes to the right of the cut line indicated in red). These pads must be used to connect the new decoder to the circuit board.

                    It's critical to cut carefully along the series of small holes, where there is a tiny V shaped notch along the side of the circuit board. Be careful to avoid the soldering pads with larger holes to the right of the cut line. I used a sharp set of sprue cutters, and snipped between pairs of holes in separate moves. Trying to cut the entire board in one snip may crack the board and damage the soldering pads.

                    Here's the board with the headlight board and decoder removed.


                    • #25
                      Looks good Verne! What 1.5 volt bulb and resistor do you use?



                      • #26
                        Thanks, Chuck...hold on, I'm getting to the lights soon!

                        More progress installing the decoder:

                        Here's the stuff needed for the install...A Soundtraxx Tsunami TSU-750 (Galloping Goose) decoder, a 1" speaker, a 1" speaker baffle kit, a section of brass strip cut down to about 65mm, and a fat guy eating a sandwich (just kidding about the fat guy).

                        We start with the speaker...drill two small holes in the side of the baffle, pass the two purple wires through, tin the leads and solder them to the speaker.

                        Before wiring this up, I added a few short lengths of heat-shrink tubing to keep the wires together for neatness' sake. I sealed the speaker to the baffle with a thin bead of Aleene's Tacky Glue.

                        Here's the rest of the decoder harness set up before installation...the blue-green wire goes to the NEGATIVE lead of the capacitor. The blue wire goes to the other lead (not soldered in place yet in the photo). The red, orange, gray and black wires get another piece of heat shrink tubing to protect them as they will snake down to the locomotive frame below the heat sink once the decoder is mounted. I shortened these four wires to just over half their original length...they could be a bit longer, but you don't want excess wires getting into the motor or getting pinched in the frame.

                        I tinned these four connections by removing 1/8" insulation, tinning each lead, then snipping them back to about 1/16". This is important, as when soldering to the pads a long lead could short against the metal frame halves below the pads. Short leads are good here! [^]

                        Next, cut a piece of gray double-sided adhesive tape to fit the entire surface of the heat sink, and apply it to one side. Then mount the decoder in the center with the leads facing right, as shown in the photo. Thread the wires up through the cab, they need to turn at a right angle to clear the cab wall. Then gently press the heat sink into place.

                        Position the loco body on its side, and tin the pads that will be soldered - the two on the near and far sides of the circuit board as indicated. Just a touch of solder is enough!

                        Starting with the red wire at the rearmost pad, solder the wires to the pads. I position each wire over the pad with tweezers, heat the pad with the soldering iron, and then slide the lead into the hole in the pad while the solder is hot. It's important to not push the lead far down, the metal chassis halves are just below the pad. Follow with orange, gray and black in sequence.

                        Place on your programming track and test the loco at this point, ensuring all wires are accounted for and won't short to the rails or each other. Testing first on the programming track should protect you from an epic fail if there is a short, producing 'magic smoke', a fried decoder and inevitable expletives. (My entire layout can be switched to a programming track, I simply ensure any other locos are on isolated tracks before enabling test track mode).

                        Here you can see the red LED indicator glowing its lovely shade of red indicating it is happy with its new loco. The sound is good from that 'big' speaker, even with the speaker just sitting in the cab!

                        WE ARE GO FOR LAUNCH, HOUSTON! The hardest part is done, next come the headlights.



                        • #27
                          Chuck, here are the requested details on headlights and resistors. Let's install the lights next:

                          Here's what we need: two 1.5 volt 15mA incandescent lamps (I used Miniatronics part 18-001-10), two R-750-1/8 watt resistors, shrink tubing, liquid insulation, and gap-filling adhesive (I used Aleene's Tacky Glue and medium gap-filling CA). The fat guy eating the sandwich is just in the way.

                          Here is a close-up of the Boulder Valley Models headlight with the bulb inserted. I sealed the bulb in place with applications of Aileen's tacky glue, starting from the back and then inserting a bead around the inside front of the headlight. Be careful to avoid getting glue on the inside edges of the headlight, particularly the rim where the lens will be mounted. Let the glue cure for 24 hours before proceeding.

                          You can also see the wires to the capacitor have been coated with liquid was getting very dry and tacky, hence the globs of insulation. It won't be visible, but I picked up a new bottle of fresh insulation for our future steps. Next, we will wire the headlights and resistors and then tuck the wiring in place so it is out of sight when everything is buttoned up.



                          • #28
                            Thanks for the info on the bulbs and resistors, Verne. I have installed the same Miniatronic bulbs using several different resistors in the 480 ohm range and up, and either the bulb is too bright and burns out quickly, or is not bright enough. I guess I need to order me some of what you use and give them a shot!

                            I've never tried the liquid tape. If you need to repair a connection, are you able to remove the stuff?

                            I'm like you...I prefer the bulb to the LED.



                            • #29
                              My pleasure, Chuck. I need to check the voltage to the bulb, but I believe it is below its rated 1.5v just from the is bright, but not that bright (if that makes sense). As for the liquid tape, it is very handy, and can easily be scraped off with a hobby knife if necessary.

                              I will post pictures of the headlight appearance, it gives a really nice, warmish glow that actually is bright enough to illuminate the track ahead when in low ambient light...just the effect I want from a headlight. To each their own, I have never been a fan of LED lighting for headlights.


                              • #30
                                As promised, here is how the headlight appears:

                                A nice, bright, warm incandescent glow, with a very small bulb size.

                                Here are the steps for the headlight and final speaker installation:

                                This looks like a rat's nest of wires, but don't worry...order will come from this chaos. I have wired the resistors and lights to test them. Note the sections of black mylar coffee stir sticks...they will serve as conduits to help keep wires out of sight when everything is buttoned up.

                                Here is testing in progress. It's essential to test before you put heat shrink tubing or liquid insulation on the connections. WARNING: double and triple-check that no exposed wires can touch each other or the rails. I have done ten DCC installs without frying a decoder, but I did kill a backup light function during testing once when a lead touched the rail.

                                Once everything tested out ok, I completed the final connections to the resistors, and covered the leads with heat shrink tubing. These will be tucked down on the floor of the cab on the engineer's side.

                                I temporarily disconnected the speaker to give me room to work, tucked the resistors down on the engineer side, the capacitor on the fireman's side, and added a piece of mylar coffee stir stick to hide the wires that will pass under the speaker when installed. The section of mylar was sliced along one side to allow me to work it over the bundle of wires.

                                Here is the reverse side...things are definitely looking neater. I touched up the brass edges of the speaker with matte black acrylic paint.

                                Here is everything in I painted the decoder and wires the same shade of green that I used for the cab walls. Keep the paint light on the decoder to prevent's mainly there to help it blend in and tone down that purple a bit.

                                I shortened the speaker leads to the minimum length necessary, and soldered them to the speaker. Next, I installed the speaker facing down with a bead of Aleene's Tacky Glue to help hold it in place.

                                And now a shameless plug for Boulder Valley Models' proprietor...the inside frame of the roof is a PERFECT press fit for the 1" speaker enclosure...I have been running another Schnozzer with no glue holding the speaker in place for more than a year. For a cast part to be such a precise fit...pretty impressive engineering!

                                I set the roof in place, glued a few details back in place that my fumblefingers managed to dislodge during the project, and took her for a test drive.

                                The Galloping Goose decoder produces great sound effects, which make this little critter a blast to operate.

                                With an engineer in position and dirty windows, there's no hint of wires or the speaker enclosure when looking into the cab. I need to fiddle with the roof to get it fitting more snugly, replace the screws holding the body to the frame, and it's ready for revenue service. This Schnozzer is going to Bill Hay, and will be hauling ore from his cinnabar mine.