Kato “Seven Stars In Kyushu” Set

[trainforfun]

Dwigth, by design, if LED lights illuminate in both directions on DC there is a bridge rectifier in that circuit, so they will also work in DCC.  If LED lights are directional in DC then since in DCC the track polarity flips many times a seconds, the lights in both directions will illuminate. They will be illuminating in the direction of the track polarity, but since it flips multiple times a seconds, you eye will see them all constantly lit.

But for either type of LED circuit DCC track voltage will safely illuminate them. Both types of circuit do have some sort of current limiting device.

5 or 6 years ago I saw a KATO Japanese set , and under the last car near the rear there was a plastic cover , if you removed it you could slip a miniature decoder to control the back up lights . You had to program it at the same time of the locomotive .
I am sure you saw these tiny decoder before

[Dwight in Toronto]

Lewis, thanks for the pointer. 
Yes, I was aware of the slide-in decoder design.  Two of the coaches in the Seven Stars set have those access hatches (I showed a pic in my first post). 
I don’t really care about shutting off the coach lights with dcc control, but some of the directional features will need to be preserved in the end car, and a decoder is needed for that.

I recently experimented with ESU’s programmable/digital lighting strip in a CPR end-of-train theatre car (there’s a Railwire thread somewhere; Sandford Fleming is the car name), and the versatility of these offerings is remarkable.  I will probably use one of these in the Seven Stars coach #7.

[peteski]

5 or 6 years ago I saw a KATO Japanese set , and under the last car near the rear there was a plastic cover , if you removed it you could slip a miniature decoder to control the back up lights . You had to program it at the same time of the locomotive .
I am sure you saw these tiny decoder before

Yes, I'm familiar with them.  The decoders sold under Kato name are made by Digitrax, but ZIMO also offers same size decoders.  Kato also sells decoders (again by Digitrax) designed to be slipped into the Kato's passenger car lighting circuit to be able to remotely control  lights.

[peteski]

Peteski … hmmm … it’s unfortunate that you can’t see the images in the link I found.
I’ll try herewith to simply post the pic of the mech and shell; fingers crossed that it works:

https://www.ntrains.org/wp-content/uploads/2020/10/IMG_1879-scaled.jpg

That worked.  Yes, any of the standard Kato-widebody decoders should fit (well except for possible vertical clearance issues).  Digitrax, TCS, Soundtraxx, ESU, and possibly others make those decoders (some are sound and some are silent). As mentioned, it is the same outline as many of Kato's American wide-body models.

[Dwight in Toronto]

Resumed investigation of Kato’s Seven Stars passenger train, starting with disassembly of coach #2, so as to see how the tiny table lamps are configured:




Here’s a closeup of the underside of the floorboard, showing the single clear plastic light pipe that constitutes the 5 table lamps within the coach.  A single LED is visible at the left edge of the lexan (?), along with three surface mount components.  Note the two tiny barrel-shaped phosphor bronze pins, which contact the thin brass strips that conduct track power from the trucks (as per typical Kato practice):




And here is the partially reassembled coach, verifying that yes, the LED’s do indeed illuminate when sitting on DCC track!  When I ordered the train from Plaza Japan, I included four packets of Japanese characters (seated figures, kitchen/serving staff, porters).  I affixed two seated passengers and an attendant in the aisle, but they are nearly impossible to see once the shell was replaced:




I next tackled the locomotive.

[Dwight in Toronto]

The loco shell came off easily, as did the factory light board:




I zoomed in on this section of the light board, simply to highlight what I believe is probably an extremely tiny diode (circled in red):




Here’s the bottom side of the light board, showing an LED at each end:




With regards to upgrading to DCC/sound, it’s been pointed out that ESU’s Kato widebody decoder might be a suitable “drop in” replacement (although board thickness is a concern).  Conceptually, it’s fairly evident how traces on the factory board could readily be modified/isolated to accommodate hard wiring of, say, an ESU Micro or Nano decoder, but again, not sure if there would be adequate top-of-shell clearance.  I’ll have to explore this a bit more.

[Dwight in Toronto]

As always, fitting a speaker is a challenge.

One thought I had was to consider how much room might be available in the rear driver’s compartment.  This pic shows the small snap-in “module” which accomodates the light pipe for the headlamps, and makes up the engineers cab:




Here’s the drivers cab module removed, giving a good idea of the volume of freed up space that would be available.  Also shown is a Roco speaker that I have on hand (15x10x9), which is almost a good fit:




A slightly smaller speaker would likely fit, and would necessitate sacrificing the dual-directional lighting, which I think I’d be ok with. 

Alternatively, there is space in the fuel tank areas on either side of the central bogie.  A small Zamac protuberance would have to be removed (circled in red):




Rather than rush into things, I think it best that I take some time for further thinking and contemplation.  Thoughts/comments/suggestions are welcome.

[Wutter]

Just a thought if you are going down the sound install path, the DF200-7000 locomotive uses dual Komatsu SDA12V170-1 prime movers but I don't think there is a sound file that exists for this engine.
Specs here: https://jrrollingstock.travel.coocan.jp/loco/DF200-7000~en.html

The older, first generation DF200-0 uses the MTU 12V 396 (I don't know how similar they sound in real life, but at least its 12 cylinders), but you could rip the prime mover files and sound logic from the ESU S0330 file.

The ESU sound files from DesktopStation are unfortunately not available online anymore, but before they were removed, I had already saved some that I can share in this case. I have the JR West Twilight Express Mizukaze sound file which is a different cruise train but has similar horns and door sounds where you could substitute the prime mover into.

[Dwight in Toronto]

@Wutter - thanks for the proto sound pointers.   I’ve been assuming all along that I would never find “the real thing”, sound-wise, and I’m willing to accept any sort of reasonable facsimile as being good enough (beggars can’t be choosers).

First things first though … I need to settle on which ESU LokSound 5 decoder and speaker might best fit within the confines of this shell!

[peteski]

The tiny component on the factory light board is a capacitor.  Since the LEDs are wired in reverse parallel (each protects its partner from excessive reverse voltage), no diodes are needed for DC directional lighting.  The capacitor is to prevent any small flashes from the LEDs from the BEMF generated by the motor when there are short power interruptions (dirty track). It shunts those voltage spikes which would otherwise cause  the sensitive white LEDs to glow momentarily.

That Roco speaker and enclosure is very bulky for N scale and it's shape seems to be wasting a lot of space.

Before you invest in the Wide Body LokSound decoder make sure there is enough vertical clearance. Otherwise you might have to go with a wired-in decoder.  I have a feeling that a nano wired-in decoder will not fit in the space under the loco, but it might become a nice enclosure for a small  sugar-cube-style speaker. Digikey sells dozens of various size sugar-cube speakers. I made a list here of the ones I collected, but by now they have even larger variety. After installing a speaker you can glue a styrene cover to enclose that space.  I would try to preserve directional lighting.

[Dwight in Toronto]

Peteski - thanks for shedding light on the workings of the factory circuit board - interesting and informative. 

The Roco speaker is just something I had kicking around, and I only showed it in order to convey, intuitively, where-&-how a slightly smaller enclosure might fit.  It came in a 2-pack, and I used one of them in the tender of the Kato Heavy Mikado that I upgraded back in December. Yes, the housing is a bit bulky, but it is one of the best-sounding enclosures that I’ve ever used.

I’m hoping to investigate shell clearance later today.

I made up a DigiKey parts list a few days ago, and included a variety of speaker sizes.  Haven’t placed the order yet though.

[Dwight in Toronto]

As has been mentioned, the ESU 58941 widebody board has a Nano decoder piggybacked on top, making it 4.5mm thick.

To check shell clearance, I shaped a piece of foamboard insulation to correspond to the Nano’s dimensions (19.6 x 8.5 x 3.2 mm), and stuck it to the Kato factory board with double-sided tape, in the same location where the Nano sits on ESU’s widebody board:






Slipping the shell back into position, I concluded that the decoder thickness would prevent proper seating … the shell sits roughly 2.3 mm too high:




On the upside, it appears that an ESU 58923 wired Nano might just work.  When I put the dummy styrofoam Nano within the rear ceiling cavity of the shell, the fit over the mechanism was perfect:




So, all is not lost, but now I have to wait for my LHS to replenish his ESU Nano stock.

[Ed Kapuscinski]

Talk about timing. One of Terri and my favorite YouTubers just rode the Seven Stars.

Looks like fun.

[Dwight in Toronto]

Ed - awesome find, man!  I’ve seen a few videos of the 7 Stars, and this one definitely highlights the fun aspects.  I haven’t found it yet, but apparently the compact piano is included in the “party” car in the model. 

I once had a business trip to Osaka, many years ago.   I enjoyed it immensely, since I had been a long-time enthusiast of all things Japanese (I still endeavour to advance my competence with Japanese carpentry, landscaping, pottery, cuisine etc).  Their culture is so very unique, charming and unusual, and the video captures a lot of that.  Thanks for sharing.

Upgrading the model to DCC/sound is in a bit of a slump as I try to locate an ESU Nano decoder locally. May have to order one from Streamlined Backshop (his prices are great; shipping … not so much!).

[nscaler711]

So as you can imagine, I have been following, But to be honest I'm not sure even fitting a decoder up in the roof of the loco would work either.
While it might physically fit, I'd be concerned about any heat the decoder may produce distorting the shell. If you can, acquire a second shell just in case. I'll keep an eye out for one but it may be easier contacting Kato Japan.
Also want to point out that the decoders dont sit flat on the boards either, they sit in a socket which leaves about ~1mm space below the decoder. At least on @Wutter awesome boards. (which thankfully Soundtraxx boards also seem to work fine on. So thank you for those!