ESU LokSound Select Micro Install in Kato N-ScaleP42 -- with 6 Function Outputs!

[RBrodzinsky]

I have completed an install of a LokSound Select Micro into a Kato Amtrak P42 Genesis.  Along with some of their other modern wide-body locos, these are fairly easy to fit, with plenty of room under the shell.  What makes this install different is that I have "activated" the two "logic level" output  functions on the decoder (Aux 3/4), to allow for 6 functions.  Why 6, well, this way I could have front / rear directional headlamps (2); front / rear directional red marker lights (with independent off from headlamps) (2); and proper flashing ditch lights (2).

To utilize the logic-level outputs, one needs to use a switch transistor, where the decoder's output is the "gate", and when the logic-level is "on"(+5V), and path is created between an output (really a sink) and the decoder's ground (-).  For those not interested in soldering itsy-bitsy electronics, Streamlined Backshop has a pre-made, 1cm x 1cm board which supports this function.  However, for this install, I went with  a smaller solution, a two-channel (handles both Aux3 and Aux4 in one) chip (FDV6301N - available at DigiKey).  This first photo shows my initial test setup of this chip, wired to a LokPilot V4 Micro.  The transistor is the upper left chip, and there are 1/10W 10Kohm resistors hung on the inputs (green and yellow wires) to the chip from the decoder. The grey wire is the decoder's ground.  The output of the chip goes to the two big resistors to the mini board, with two LEDs, and the decoder's blue wire (common +)

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For a LokSound Select Micro, these extra functions can be found on the bottom of the board. This photo shows the connections. In this photo, the Orange with Blue dots is Aux 4, White with Blue dots is Aux3, and the gray with black dots is ground

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To use this little circuit, I cut a small square of 0.02" styrene, just larger than the chip and solder points, and then mounted the chip using Bondic (UV cure adhesive). This also let me encapsulate the solder joints in a very small package (less than 5mm x 5mm).

As mentioned, the key for all of this was to enable the front and rear red marker lights, with the ability to turn them off independently of the headlights (headlights must be on for the markers to be on).  I had read many posts of people not adding these marker lights in N-scale, as it would "require shell modification".  Well, actually, no it doesn't!  The little red plastic pieces Kato installs can pull out quite easily, and there are even holes already available to run the LED wires through. 

Here is the rear housing assembly from shell. You can see the rear headlights in the center, and the two 0603 SMD red LEDs I have installed.  They are mounted right where the holes in the shell are, and the magnet wires go through the holes that Kato's plastic piece mounts in

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and here they are, lit

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Similarly, here is the cab/light insert from the front of the loco. You can see the two LEDs mounted at the bottom of the cutout, and the magnet wires going through the (removed) plastic insert mounting holes.

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I wire these red LEDs in series.  In this photo (sorry for bad contrast) of the underside of the cab detail piece, you can see the two ditch lights with their cut light pipes, a 1206 warm white LED mounted to the main light pipe for headlight and number board, and in the bottom left corner, a small piece of circuit board that I used for the series connection on the red lights.

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[RBrodzinsky]

Here is the decoder, speaker (8x12 mm Soberton w/ Keystone Details enclosure) and keep alive capacitors (3 20V 150uF)  installed in the fram, with light attachment boards at front and rear.  In the center of the photo, just above the orange, blue and yellow wire, you can see the small chip circuit on top of the decoder (wrapped with Kapton and firmly affixed.  I always test the install for sound and motor function prior to wiring the LEDs.

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And, here is the shell with all LED wires attached to the boards

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Using magnet wire, it is not difficult to get everything to fit nicely under the shell.

[RBrodzinsky]

And now, photos of the results:

Front of loco, head lights and ditch lights on (Forward)

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Front of loco, red marker lights on (Reverse)

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Rear of loco, head lights on (Reverse)

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Rear of loco, red marker lights on (Forward)

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[carlso]

Very nice work Rick. Thanks for sharing.

Carl

[RBrodzinsky]

Thanks Carl. I learned a whole lot about the inner secrets of these decoders, due to the USPS misplacing my first package from Bryan. If everything had arrived as planned, would have been an almost mindless conversion of “just connecting wires.”

[tehachapifan]

Wow, great install!!

[milw156]

Disclaimer: no speaka de electron language, (kinda like women, I appreciate, but don't understand)
what is to stop one from using logic function (on/off correct) to run the LEDs directly thru the usual resistors?
I want to put a LokPilot into an FP7, and was thinking of illuminating the number boards using AUX 1, which is a "logic level" output also.
And I just placed an order with Brian!

[RBrodzinsky]

Disclaimer: no speaka de electron language, (kinda like women, I appreciate, but don't understand)
what is to stop one from using logic function (on/off correct) to run the LEDs directly thru the usual resistors?
I want to put a LokPilot into an FP7, and was thinking of illuminating the number boards using AUX 1, which is a "logic level" output also.
And I just placed an order with Brian!

First, check out this recent thread: https://www.therailwire.net/forum/index.php?topic=43338.0

The key is whether or not consistently driving >0.5mA from these will do permanent harm to the decoder.  Per the specifications, logic level decoder outputs are only rated to support this amount of current.  In the above thread, I demonstrated pulling about 3.5mA, and the ESU decoder supported that for a couple of minutes of testing, but I did no long term test.   Polling all the electronics experts I know and here on TRW, the  consensus was that this was not a good idea; and with NMRA and NEM specs, keeping within them was the safest to do.  Testing at 0.45mA showed that the lights were just not bright enough (you need to get to about 1.25 - 3 mA for the SMDs to shine).

If you want to try, remember that it is NOT the normal wiring.  Normal AUX outputs are a "sink" to ground (-), with the blue wire being the common (+) (i.e. the current flows into the AUX "output").  When the function is "on", the connection to ground is made; otherwise it is "open".  So Blue = ~12V, Aux output = 0 V, and the circuit supports approx 150 mA.    Hooking up the logic level means you need to use the LL output in place of the blue wire, but it is now only +5V, and you need to connect to ground, with specified current of 0.5mA.    If you choose to go this route, please let us all know the long-term reliability  (since my project was a LokSound (3x cost), not a LokPilot, and for someone else, I chose the supported route). 

[milw156]

Thank
Thanks for the education, I knew just enough to get me into trouble and almost did! I figured the likely issue would be blowing an LED, not frying the decoder. Repeat previous statement!
Rick

[jsleee]

Rick, did you reuse the DC board?  I took mine out and now I am having issues with the copper making contact with the wheel pickups.  I cut off the end of the KATO dc board and tried it in the front but still having issues.  I may have to super glue the copper down.

[RBrodzinsky]

Rick, did you reuse the DC board?  I took mine out and now I am having issues with the copper making contact with the wheel pickups.  I cut off the end of the KATO dc board and tried it in the front but still having issues.  I may have to super glue the copper down.

I used an older E/F B-unit "blank" DC board (no circuitry).  You can see it under the decoder in the pictures. 

Normally, what I do with most Katos with the long copper strips is make a dummy board from 0.020" styrene, cut to size. This allows for holding the strips in place, and protects the top of the motor from wires. Cut the slots for the Kato plastic clip, and it holds the styrene in place (or use Kapton tape)