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CaptOblivious

DCC Decoders for Cab Cars/End Cars

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mbloes

Ok so I finally did this the way I envisioned – and by “this” I mean dcc my end cars so that the lights will change based upon the direction of travel.  My goal was to merely wire the decoder directly to the lightboard with minimal modifications – so, no additional resistors, no cutting pcb traces, etc.

 

The train I chose was a Greenmax 4905 “Series 103-500 Bantan Line” plus the 4906 add-on set.  This is a two car train and the add-on set is an identical two cars (minus motor).

 

I used the Nagasue “DF11r4”  function decoder. This is a function-only, bipolar decoder, which is exactly what I was looking for.  I purchased 8 of these at a very reasonable (to me) US$160, which also included Y400 of shipping charges.  The package came within a week.

 

Finally, I used the Greenmax 6605 lightboards.  These are not the lightboards for this train per se, but the layout and shape are similar enough and they wound up ultimately working.  I just soldered the leads from the decoder to the little springs on the lightboard. You can see the decoder and the lightboard in the front car here:

 

8383473425_e1ab153447_z.jpg

103 dcc 1 by mbloes, on Flickr

 

I used a Digitrax DZ125 for the motor.  Here is the motor and rear car installation:

 

8383506361_7884229d65_z.jpg

103 dcc 2 by mbloes, on Flickr

 

Finally here is the four car set numbered as it would run, from right to left – 3 decoders; 4 cars (!):

 

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103 dcc 3 by mbloes, on Flickr

 

As an aside, because this was a two car set, the motor car would otherwise be the front car / lights car.  I didn’t really want to put two decoders in one car so I moved the motor car to the #3 car.  I could do this because both #1 and #3 are essentially identical.

 

This project was a huge success with all decoders performing as planned. And Shuhei Nagasue corresponds in excellent Eigo, as I found out when I needed help with some settings.

 

Should anyone decide to use these decoders, I have translated the CV settings sheet from 日本語 , so just let me know if you need it!

Edited by mbloes
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Martijn Meerts

What's the size of the decoder?

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mbloes

18mm x 11mm x 2mm thick. There are no chips on the backside, only pc board.

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Martijn Meerts

I already thought it looked a bit big :)

 

It'll likely work for many cab cars without having to worry about it being too visible from the outside though.

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CaptOblivious

I will second Nagasue-san's responsiveness. He is very good at responding to emails, assisting in troubleshooting, and writing in clear English.

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mbloes
I already thought it looked a bit big :)

 

It'll likely work for many cab cars without having to worry about it being too visible from the outside though.

 

Yes, the length and width aren't a problem and its thin profile really makes it discrete.  My problem, though, is my "not too well thought-out" wiring job, which is totally visible through the windows (especially using yellow and white).  I wasn't focused on this though, I just wanted to get it working.

 

Now, my goal will be to wire the decoder solely to the chassis and let the lightboard make contact with the chassis as originally designed for analog.  This should be doable - at least with Greenmax - because they use those long copper strips in the chassis where it's easy to isolate the relevant areas for dcc'ing.  We'll see. I'll keep you posted.

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mbloes

Update for 2014: My most sanitary installation yet!

 

Once I got the basics down for installing bipolar decoders (see my posts above), my goal was to clean up this installation by wiring the decoder to the chassis only and let the lighting module contact the chassis as designed by Greenmax.  This was a relatively easy mod as the chassis has these long copper strips that can be cut up in order to isolate the track power from the light power.

 

My cut / isolated copper strips (cut is at the white arrows):

 

post-145-0-21304300-1403639648_thumb.jpg

 

The modified chassis and decoder, ready for installation:

 

post-145-0-33524200-1403639485_thumb.jpg

 

The completed decoder installation.  Note that, when the body is installed on the frame, the little spring thingies on the light module will make contact with the copper pads.

 

post-145-0-84728200-1403639947_thumb.jpg

 

A little programming and off we go!

 

 

 

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kvp

How did you prevent the two end pices from sliding sideways and contacting the pickups?

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mbloes

If you look closely, the reason I cut the copper strips diagonally was so that the little locating pins continue to retain those end pieces (while still allowing both bogies to conduct).  Also, the copper strips are countersunk into the plastic frame (it's hard to see this in my photos) so this limits any movement as well.  Finally, I put a dab of silicone seal underneath the copper for that "last word" in retention.

Edited by mbloes
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kcraiglowe

I'm new to this forum... I have an N scale Kato Hayabusa. I'm having trouble installing the FL12 decoders into the end cars to control directional light white/red.  Since the decoder installs from the bottom of car and not thru the passenger compartment. It doesn't seem to want to close. Do I need to cut the tips off the tab that hold the PCB in? The instructions if not for the unit I have but Kato USA says that it's the right board and should fit.

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post-2498-0-95024800-1405283474_thumb.jpg

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kvp

The decoder should be pushed forward, so the contact pads are under the pickup strips. Just make sure, you insert it good side up and in the right direction. (there are 4 possible ways to do it, only 1 works and 2 could even damage the board) The idea is that the 2 track pickup pads should contact the 2 track pickup strips and the light output pads should contact the 4 light connectors.

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Jaya NAITHANI

Hi,

 

I just bought two Kato train sets, 10-555 and 10-857. I installed the EM13 and FL12 into them. I have Fleischmann track with ROCO multimauss system. Once I install a new locomotive and assigns a CV, it askes for V=. I give the same value to both. Once I press OK the train slightly moves on the track. When I try to run, it does not move at all. Could you please suggest me something?

 

Thanks in advance!

jn

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kvp

Program each decoder separately. Only the motor decoder will be able to generate a feedback signal (the slight movement), but all 3 should be ok and have the same address. Test each car separately on the main tracks to see if they work by setting the current train address to the one programmed into the decoders during the programming. Always reboot the decoders after programming by lifting them up from the programming track and placing them on the main tracks, this should get them out of programming mode. For the motor decoder, it is possible to read back the programmed address, so you can check if everything is ok.

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Jaya NAITHANI

Thanks! The trains are running now! I stil have some problems with the lights on the rear cars of the two trains. Also the rear car of 10-857 is derailing very frequently.

 

Thanks again for the suggestion!

Best regards!

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E6系

Hello,

 

What is the problem with the lights on the rear cars?

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Jaya NAITHANI

Hi,

 

Lights of the thunderbird's front car was initially red and after some time became white by itself! Good for us... But the rear lights still show no signs in both trains. The front and rear cars of Shinkansen are derailing all the time. Maybe it is the problem with the tracks. We have Fleischmann tracks. I am reading the reviews about these tracks and they are not that very encouraging.

 

regards

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E6系

Hello,

 

I presume you have tested the car without the decoder installed, and that it works fine in DC mode.

 

The FL-12 decoders must be installed with the two large pads facing the track and the four smaller pads facing up.

 

Sometimes the decoder fit will be tight and not make contact with the four pads.  A little low-heat solder on the four pads can remedy this.  Alternatively, lightly sanding the edge of the decoder board, or using a dremel tool.

 

If the lights are operating the wrong way around, that is to say, red for forward and white for reverse, remove the decoder and rotate 180°.

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Melandir

I have a dumb question for this topic, can I use the Digitrax dz125 has bipolar function decoder to avoid to rebuilt the lightboard for non dcc friendly trains?

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kvp

As far as i can tell the DZ125 doesn't have a bipolar function output, just the normal pull to ground.

 

But you can add a simple home made circuit between the decoder and the light board to make it bipolar. You need a small H bridge motor driver ic (preferably 6 pin), two pullup resistors to common+ on the led outputs connected to the driver ic inputs, common+ connected to the voltage input of the driver ic and two diodes from the ground of the driver ic to the tracks. The outputs of the driver ic can go to the unmodified light board. If the decoder doesn't have a common+ (6 pin decoders), then you need two more diodes from the tracks to generate a common+ (or a 4 pin diode bridge chip to generate both common+ and common-).

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Webskipper

How do you bench test Kato Decoders?

 

I'm going through my inventory and finding that the FL12 (29-352) either loses memory or fails to program and function.

 

I've re-installed the Cab decoder. Cab directional light inoperative. Interior Lights illuminate. New decoders work; so we know the pickup strips are doing their job.

 

Any hints before I pack up 4 decoders to ship to Kato USA?

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kvp

Normally you install them in a car that is known to work and after testing you replace the good decoder. If that is still working, then the decoder in question has a problem.

 

On the other hand, connecting led lights on the output with the same current consumption (aka. series resistor) and led polarity as Kato cab lights and powering the decoder through its inputs should work. There are very good pogo contacts available for this, but you can create some kind of contact strips imitation too. For motor decoders the same is true, except you have to connect an inductive DC load (a real DC motor) to the outputs. Using an oscilloscope to find problems while under load is overkill, but possible.

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E6系

I have a dumb question for this topic, can I use the Digitrax dz125 has bipolar function decoder to avoid to rebuilt the lightboard for non dcc friendly trains?

Hello Mr Melandir,

 

The FL12 is bipolar, but the DZ125 and the new DZ126 are not.  To avoid modifying light boards on older trains you can solder wires to an FL12 and use it with other LED boards on, say, Micro Ace or Tomix trains.  However, I would not try this in models that use bulbs.

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E6系

How do you bench test Kato Decoders?

 

I'm going through my inventory and finding that the FL12 (29-352) either loses memory or fails to program and function.

 

I've re-installed the Cab decoder. Cab directional light inoperative. Interior Lights illuminate. New decoders work; so we know the pickup strips are doing their job.

 

Any hints before I pack up 4 decoders to ship to Kato USA?

Hello Mr Webskipper,

 

If you have some FL12 working but others not, I suggest you return to Kato.

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Melandir

I have a question that involve this thread

 

does anyone have on hands the links to Kato website where is shown how to modify the end cars light board to be used for DCC?

 

thanks for your time and help

 

EDIT:

I have found them

 

JP http://www.katomodels.com/hobby/dcc/dcc_tips/light_kato.shtml

 

EN (Google) https://translate.googleusercontent.com/translate_c?depth=1&hl=it&ie=UTF8&prev=_t&rurl=translate.google.com&sl=ja&tl=en&u=http://www.katomodels.com/hobby/dcc/dcc_tips/light_kato.shtml&usg=ALkJrhiT4-Bu40yu_6ayEgOtiPq12vx1fg

Edited by Melandir
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