Stopping flickering lights in TGV coaches



Ever since I bought and installed Kato's LED coach lighting in my Thalys set, it has had that annoying on-off flickering. Clean tracks and clean wheels did not seem to make any difference. The lighting circuit and LED is mounted on an L shaped piece of plastic, that is supposed to wedge firmly into a slot inside the car. No matter what I did, it never seemed to get a good solid contact. I also suspected the contact between the wipers on the trucks and the copper contact strips. Finally I had enough.

A discussion with the folks at Ngineering, and an order, brought me some 68 uf tantalum capacitors, 1/2 amp bridge rectifiers, and super flexible #29 wire. The space available was a mere 1/2 inch cube. Maybe.  By the way, this is N scale, DCC.....

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First I had to figure out the best way to put the components together, as compactly as possible. The plan was to solder the wire directly to the wheel contacts, then to the AC side of the rectifier, and solder the DC side, + to + , to the capacitor. While it was recommended to connect 3 capacitors in parallel, I only had room for one.

So, first I soldered the capacitor to the middle of a short piece of wire, leaving some tinned wire exposed for later connection to the lighting contacts and a little bit on the other end to attach to the rectifier. Then wired the + and - from the rectifier to the capacitor. And soldered some wire, about 3 inches long to the AC side of the rectifier. I tried doing shorter wire, but later had trouble threading it through the holes in the coach and then down through the hole in the floor of the passageway:.

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Everything is tight and compact. You can see in the above photo that I have removed the copper strips that the trucks contact. They were just in the way, and I was bypassing them anyhow.

Next I folded over the tinned ends of the wire from the capacitor, and soldered them to the lighting contacts on the car. The capacitor and rectifier are now in place, and wired. Next, the feeder wires from the trucks to the rectifier. You can see in this next example the two black wires to the trucks are too short. They need to be fed through the coach-end, and down through a hole in the passageway.

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I drilled a tiny hole (these #29 flexible wires are very small diameter) in the end of the coach. Then, working from the bottom, I drilled another slightly larger hole up through the truck pivot. I went through the truck pivot so as not to interfere with the turning action of the trucks. Then I fed the two #29 wires through the end of the coach, and down through the hole in the pivot.

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Then, I cut the wires short, an soldered them to the wheel contacts:

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Finally, I took them out to the barn and tested them. Yeehaaa!

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el Gato Gordo2017-02-25 13:58:37

Comments

  • Gordon,

    Isn't the problem with the TGV (and other similar Kato constructions such as the 425/426) rather that each coach only gets electricity from one bogie only? I.e. each coach relies on a very small wheelbase for electrical pickup. Another way I have seen this issue solved (and which I have planned for an upcoming conversion on my 425) is to have connector plugs between the coaches so that they are all wired together, which means all wheels are used for electrical pickup which reduces the likelihood that any one coach will go without power.

    Misha

  • el Gato Gordoel Gato Gordo Colorado Spring
    Misha, you are right that the TGV and ET425 have shared bogies, and this could exacerbate the problem.  Markus, I hadn't thought of wiring the lighting in the coaches together.  I will have to try that with my ET425.

    If you look at my first photo, though, you can see the L shaped bracket on which the LED & circuit are mounted.  I have fiddled with those for years, and never achieved satisfactory connection in all cars.  It is not that the lights were flickering going over a dirty spot, or over insul-frogs, but just plain acting erratically. 

    I like the way the wheel axels socket into the copper strips for a pick up.  Soldering the superflexible wire directly to the copper, thence to the bridge rectifier and capacitor, and soldering directly to the LED contacts has solved the problem, essentially making a hard-wired contact between the wheels and the LED.
  • Gordon,

    If you redo the 425, here's a how-to on digitalizing the 425 with a single decoder and using all wheels for pickup (in German though - but pucsi should be useful):

    http://www.1zu160.net/digital/einbaubsp/kato-et425-V2.php

    http://www.1zu160.net/digital/einbaubsp/kato-et425.php

    I currently still use the Kato decoders but I'm not happy with them. I finally got the main decoder to work properly (I have an aftermarket wormgear that makes the train run more realistically slower which was messing with the preset impulse period of the decoder). But my main issue is that the interior lighting decoders from Kato keep dying on me even if I run the layout on a lower voltage setting. So the above conversion is on my to do list as well.

    Misha

  • edited March 5

    Hi Gordon,
    I was blown away when I saw your solution, brilliant !!!
    I was searching for something similar, but yours solution did it!
    By the way, I use this method, soldering, in all my TGV loc's and Japanese shinkansen's
    I do not want any "moving" copper parts, expect de wheel turning in it's copper "bowl".
    Oh one question, can you post a picture(s) of the wires entering the cabin/coach?
    (My current project is the TGV Duplex, even less space than the single deck one ........)

    keep up the good work,
    regards,
    gerwin, holland

  • el Gato Gordoel Gato Gordo Colorado Spring

    Hey, Gerwin! Here is the photo you requested.

    I hope this is helpful. When you do your Doppelstock TGV, post some photos of how you do it. I can also be found on nscale.net as el Gato Gordo.

    Cheers! Gordon

  • Hi Gordon,

    Thanks for the picture.
    I need one from the other side, so you can see the text on de capacitor.
    Did you have to alter the cabin? Or to you enter below the partion wall?
    So the capacitor is an energy storage unit 100uF/25V ?
    With any additional circuitry?

    Regards,

    Gerwin

  • el Gato Gordoel Gato Gordo Colorado Spring

    Hi, Gerwin

    The capacitor is 68 mF. 100 would be better, but probably larger. The wires come into the cabin under the wall; I don't remember whether I carved away any of the bottom of the wall. No additional wiring. Two wires from the wheel contacts to the rectifier's ac contacts. Two wires to the capacitor's contacts, but continuing on, unbroken, to the lighting. No additional wiring. I have some spare capacitors, so I will post a photo later.

    Are you in the Netherlands or Holland, Michigan? We are coming to the Netherlands in the Spring of 2022 for a bike and barge tour.

    Cheers! Gordon

  • el Gato Gordoel Gato Gordo Colorado Spring

    Here is a photo of the packaging. On the left are the bridge rectifiers (converts ac to dc current); on the right are the capacitors.

    I also photographed the capacitors through the packaging. The writing can be made out. I'm glad you are asking these questions. I did this so long ago that I had forgotten all about it and that I have spare material to use in different trains.

    Cheers! Gordon

  • el Gato Gordoel Gato Gordo Colorado Spring

    Oops. I forgot to post the 2nd photo.


  • Gordon,
    Thanks for the info.
    Because the TGV Duplex is lower (upper and lower deck) I have to come through the partion wall.
    Also the power pickup point is on the other side of the coach.
    If everything is finished, i will post.

    Yes, from the Netherlands!!

    Regards,

    Gerwin

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