Author Topic: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale  (Read 4243 times)

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peteski

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #75 on: February 07, 2025, 10:43:51 PM »
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Dwight,
Fiber optics are not just a piece of glass or plastic.  They actually have an inner core and outer cladding, both from transparent material, but each has a different refractive index.  That is what keeps the light waves inside the optic.





If the fiber is bent too sharply, some of the light will escape, with the amount depending on the sharpness of the bend.





And no, wrapping the fiber with some reflective material (like metal foil or white or silver paint)  will not bounce the escaped light back into the fiber's core.

If you feel like getting some more technical details, check out https://en.wikipedia.org/wiki/Optical_fiber  I always like to educate myself about the technology or chemicals I use in my hobbies. I think it makes me a better modeler if I understand how things work.





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Dwight in Toronto

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #76 on: February 08, 2025, 08:53:01 AM »
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Peter - thanks for the speedy reply, and for taking the time to compose such a comprehensive writeup.

Interesting stuff, and I am now sufficiently ‘enlightened’ to proceed with the build.  Although I am a little concerned about the two 90 degree bends that were required … just need to ‘have at it’, and see what happens.

peteski

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #77 on: February 08, 2025, 10:11:06 AM »
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That's what experimentation is all about, and you're welcome.  ;)
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Dwight in Toronto

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #78 on: February 08, 2025, 12:31:39 PM »
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Well, I was well on the way to trying out the fibre optic “backing up” lamps.

I drilled the pass-through hole in the coach floor, and confirmed that the fibre light conduits would fit snugly along the bottom of the frame, with their light impingement stems properly protruding into the coach interior.  As shown in the following pic, I then soldered a bright white 3mm LED to the ESU digital lighting strip, positioned so that the LED shines downwards, directly over the hole in the floor where the fibre stems would protrude into the car interior:




The next step would have been to cover the LED with a shroud made from heat shrink tubing, to ensure that all of the light from the LED would be confined around the two fibre stems.

Before wrapping it all up, I wanted to check out the new LED on LokProgrammer, and configure the file so that the LED would only illuminate when the train was reversing.  The upside was that the 3mm LED was functional, and it was nice & bright.  The downside was that the LED illuminated as soon as there was track power, and no matter what I did with function mapping and output configuration, I could not get the LED to turn off (let alone be controllable in any way).

By temporarily flipping around some of the function mapping, I was able to confirm that my settings were correct … I easily configured one of the other sets of LED’s to switch on as soon as direction was reversed. 

My conclusion is that this output on the light strip is faulty, generating an “always on” condition.  I’ve had this happen with two ESU 58741 sound decoders in the past.

It was a lot of careful, precise, detailed work to get to this point, and I’m entirely convinced that the approach and technique would have been successful.  But alas, a most disappointing outcome in the end. 

I think I’ll epoxy the fibre conduits in place just the same, so that if anything disables the digital light strip down the road someday, it would be relatively easy to try again with a replacement strip.

Dwight in Toronto

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #79 on: February 08, 2025, 04:01:05 PM »
+1
Curiosity got the better of me … I just had to know if the fibre optic light pipes would have done the trick, so I finished off the install and put everything back together. 

It was satisfying to see that the overall approach worked better than I thought it would have.  Here is a quick-&-dirty pic of the reversing lamps illuminated:



The red glow in the coach is the 3mm LED shining through the heat shrink shroud. 

Here’s the same pic, but with all of the rear end fascia lights turned on, and the coach interior lit up:




As mentioned in the previous post, the downside is that the function output for those lower-most lamps was faulty “out of the box” - they light up as soon as the wheels pick up track power, and cannot be turned off.  This isn’t what I want, so I will be removing the LED. 

Too bad, because I quite like the effect.  Despite this last wee bit of bad luck, the project itself was a lot of fun, and contributed to a good deal of learning - lots of new tricks & techniques added to the model railroading toolbox!

Many thanks to all who followed along, and especially to those who offered advice and comments.

peteski

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #80 on: February 08, 2025, 11:00:41 PM »
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Good to know that the optical fibers did not lose too much light in the sharp bend.
Which specific output on the light strip did you try (and feel is defective)?
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Dwight in Toronto

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #81 on: February 09, 2025, 09:01:45 AM »
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Good to know that the optical fibers did not lose too much light in the sharp bend.
Which specific output on the light strip did you try (and feel is defective)?

Peter, as you will know from looking at your own light strip, there are 3 pairs of solder pads for LED’s:

- One pair comes with two 3mm red LED’s attached, has a resistor onboard, and is mapped to F0 so that it can be treated much like the “F0 Directional Headlight” function on a conventional ESU locomotive decoder (ie - you can configure it to illuminate the LED when the train is going FWD, REV, or both).  In my case, I replaced the red LED’s with two 0402 white ones wired in series, and used these for the rear marker lamps, set up to come on whenever the locomotive headlight is on, in both fwd & rev.

- Another pair of solder pads is available as a complement to that first pair, in that they also have a resistor onboard, are also mapped to F0, and can accomodate a second LED, which is intended to be another directional headlight (it too can be configured to light up in FWD, REV or both). ESU provided this additional F0 output so as to give modellers a front and rear headlight for cabcar/commuter operations.  In my setup, this is where I soldered the 3mm white LED, which is shining down onto the ‘light collector’ ends of the fibre conduits … THIS is the faulty output that is permanently “stuck on”.

- The third pair of solder pads does NOT have a resistor, and is mapped as AUX1.  In my case, I soldered in a 8K smd resistor, added two 0402 LED’s in series, and installed these as the two spotlights/floodlamps located above the big picture window.  I set these up to toggle on/off with F6.

Pete, it would be interesting if you could pop some LED’s onto your light strip, and maybe replicate what I’ve done, just to see if the 3 outputs work properly for you.
« Last Edit: February 09, 2025, 01:41:58 PM by Dwight in Toronto »

peteski

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #82 on: February 10, 2025, 12:52:06 AM »
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Dwight, you didn't go into details. I assume that you connected your white LED with a series connected 8k resistor between the pad marked FL (Front headLight) and 5V?

The instructions state:
Optional front light
For operation in Control/Cab car, as shown in Fig. 5, a white front light can be added. Only white or
yellow LEDs with a maximum current consumption of 15mA may be used. A series resistor is already
installed. The front light works like the rear light, directionally.
External load (AUX1)
To switch external loads (eg toilet lighting, destination signs, etc.) a separate transistor output with
a maximum current of 100mA is available. It is shown in Fig. 6, and is preferably connected to the
voltage + U. A series resistor for LEDs is not installed. The U + voltage is not buffered by the power
pack and the control to adjust for brightness has no effect.


So the FL output does have on-board resistor and use 5V for positive voltage connection.

Reading between the lines I suspect that the FL output is a logic output limited to 15mA (as they mention "transistor" and U+ in the description of the AUX1 output).  We both know the ESU manuals are often not very clear.

I hooked up my new light strip decoder to the booster output, and also connected a white LED directly (no resistor) between FL and 5V pads.  The decoder still has the default factory configuration and it works as described in the manual.
I connected the decoder to the track output of my DCC system and dialed up short address 3 on the throttle. with F0 off neither the "FL" LED nor the red marker LEDs are lit.  When I turn F0 on, then depending on the direction set on the throttle either the red LEDs or the FL white LED gradually lights up.  When F0 is left on and I change direction the decoder switches between the red lights (rear markers) and FL LED.
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Dwight in Toronto

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #83 on: February 10, 2025, 09:01:44 AM »
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Dwight, you didn't go into details.

Hmmmm, and here I was, thinking that I had provided a pretty coherent description!   :|

I assume that you connected your white LED with a series connected 8k resistor between the pad marked FL (Front headLight) and 5V?

No.  The pad marked FL & 5V is the faulty output that is perpetually “on” with my light strip.  I saw that the instructions say that the resistor is already on-board, so I did not use one.  Good to hear that this output worked directionally for you; no such luck for me.

It was the External load (AUX1) output (pads marked UB and F1) where I used the 8K resistor (to illuminate two 0402 LED’s, in series, that constitute the spotlights above the picture window - mapped to toggle on/off with F6).


The good news is that I implemented a workaround that has delivered a satisfactory result.
I found that my preference was to have the two coloured marker lamps always lit up.  So, I simply disconnected the -ve lead from the working directional pad where the factory red LED’s had been fitted, attached a white wire, and ran it to the ‘always on’ FL pad.  Conversely, I soldered the -ve lead from the 3mm LED to a yellow wire, and attached the other end to the known-to-be-working directional pad where the factory red LED’s had been fitted.

Voila - the coloured marker lamps are always on (which I like), the overhead floodlights are controllable with F6, and the lower ‘backing up’ lamps illuminate whenever the locomotive is reversing.  I’m a happy guy!

peteski

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #84 on: February 10, 2025, 09:00:32 PM »
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I guess I confused things.  I sometimes missunderstand things (and I read your post 3 times).  Probably because you mentioned both FL and AUX1. I guess if the writeup just stated "The problem with constantly on LED is when it with its 8k series-conneted  resistor when it is connected between AUX1 and +U".  Not your fault.

I'll test the AUX1 output for you (I still have everything set up for testing).
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Dwight in Toronto

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #85 on: February 11, 2025, 08:35:55 AM »
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I guess I confused things.  I sometimes missunderstand things (and I read your post 3 times).  Probably because you mentioned both FL and AUX1. I guess if the writeup just stated "The problem with constantly on LED is when it with its 8k series-conneted  resistor when it is connected between AUX1 and +U".  Not your fault.

I'll test the AUX1 output for you (I still have everything set up for testing).

But the LED(s) with the 8K series-connected resistor on AUX1 is not the problem - that output, which requires the user to add a resistor, works fine.  (But yes, please do test that one as well).

It’s the pad marked FL and 5V that is faulty - the one that ESU mentions can be used for cab car applications … THAT output is perpetually “on”.

No worries - I’ve got things working satisfactorily, finally!

peteski

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #86 on: February 11, 2025, 09:15:11 AM »
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But the LED(s) with the 8K series-connected resistor on AUX1 is not the problem - that output, which requires the user to add a resistor, works fine.  (But yes, please do test that one as well).

It’s the pad marked FL and 5V that is faulty - the one that ESU mentions can be used for cab car applications … THAT output is perpetually “on”.

No worries - I’ve got things working satisfactorily, finally!

You're really getting me confused.  There are only 2 extra outputs on that board.  One marked FL (Front Light), and the other marked F1 (AUX1).

My original post *WAS* describing testing the FL output for you (with just the LED, and no resistor added).   The LED was controlled by F0 and the direction of the model.  I also quoted a section of the manual (in italics) descrbing both FL and F1 functionality.

Now I just tested the F1 output and for completeness trying both U+ and 5V for the positive side of the LED with series-connected 8k resistor. With default factory mapping configuration I can control that LED using the F1 key on the throttle.  Of course when using the 5V instead U+ the LED is a bit dimmer.

I don't know what else to try for you.
« Last Edit: February 11, 2025, 09:17:12 AM by peteski »
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Dwight in Toronto

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Re: Crafting CPR’s ‘Sandford Fleming’ Theatre Car in N Scale
« Reply #87 on: February 11, 2025, 03:51:28 PM »
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Peter, as always, thanks for contributing your help and advice.  Apologies for the confusion.

You’ve replicated how I added LED’s to each of those 2 extra outputs, and you confirmed that both outputs work as intended on your light strip.  Thanks for that; no need to try anything else.

On my light strip, the FL output (with just the LED and no resistor) lights up the LED as soon as the strip receives track power, and the LED cannot be controlled by F0 nor the direction of the model.  Hence, a faulty decoder output.

My F1 output, with series-connected 8k resistor, works properly in the same manner as yours (except I mapped the output to toggle with F6 key on the throttle instead of factory default F1).

I think we’re good bud - thanks for the support!