ESU LokSound Select Micro Install in Kato GS-4

[RBrodzinsky]

A bit over nine years ago, I got my very first loco - a Kato GS-4, SP #4453.  At first I ran it with DC, then put installed the Kato EM13 drop-in decoder, and finally had someone install a SoundTraxx Tsunami 750 with Heavy Steam sounds.  This has, and always will be, my favorite loco, but it always had a few issues.

The issues were never earth shaking, but there were items like the front headlight was not on a DCC function key, but still controlled by the rails; the front Mars light, and rear headlamp were on F0. Also, with age, it grew to have an intermittent short problem that would reset the decoder (and sometimes, it would mess up the decoder settings) which I knew I needed to address.  So, I had been wondering if I wanted to open this beast up and put in a LokSound.

Well, wouldn't you know, Matt Henry from ESU came out west earlier this summer and recorded old #4449 up along the Columbia River and in Portland. Last week, the sound file for it was released. With a show next weekend, in San Luis Obispo, I wasn't certain I wanted to possibly put the GS4 out of action, but.... Took me a bit longer than I anticipated (all told about 10 hours), primarily trying to figure out the short, but here it is!

These are in process photos (I honestly forgot to take a final opened-up photo with everything neat). Here is the overall view (the basic neatening is shortening up the wires in the tender).  Rather than our usual trick of just putting in some tantalum capacitors, for this baby, with its huge tender, I went with the ESU Mini-Keep Alive circuit. This enables one to read and write with the LokProgrammer (caps can interfere and need to be disconnected).

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Here is close up of the loco. I created a dummy light board out of 0.020" styrene, and mounted two 1206 SMD LEDs. Each LED is buffered by a 1K-ohm SMD resistor. The motor is fully isolated from the frame, with direct wire connections to the poles. No reliance on the drawbar.

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Here is the tender. I created a small soldering PCB to connect the decoder wires and the seven wires coming from the loco.  7 wires!  Yes, I also bypassed the drawbar for the track power, and tapped 00-90 holes into the lower frame under the cab, and ran a red and black wire back. The drawbar is now electrically neutral.

The wires going to the keep alive, as well as the rear headlamp LED are long, since they are attached in the tender's shell, so I need the tether to be long enough if needed.
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So, without further ado, I present this video of the finished product. Besides the prototypical sounds, the sound is much richer with the Soberton 8x12mm speaker and Keystone Details Shapeways enclosure than with the original Soundtraxx install.

[peteski]

Sounds good!
I would have kept the drawbar pickup connections - they don't seem to be unreliable to me. If you did that and also installed 2 diodes in the loco (to generate the common positive "blue" voltage for the LEDs), you could have only needed 4 wires connecting the tender.

[tehachapifan]

Sounds great!

[RBrodzinsky]

Sounds good!
I would have kept the drawbar pickup connections - they don't seem to be unreliable to me. If you did that and also installed 2 diodes in the loco (to generate the common positive "blue" voltage for the LEDs), you could have only needed 4 wires connecting the tender.

Thanks

Well, it turned out it was the wire in the lower draw bar (track pickup) causing the intermittent shorting problem. One side had gotten slightly bent over time (I know, I probably caused it in handling at some point); so as I was trying to fix, I broke.  Rather than wait the week for Kato to ship a new draw bar (and not have the loco for next weekend's show), I snipped the other side, tapped the holes, and added the wires.

Please tell more about the dual diode circuit.  I have always wondered about installs where the blue wire isn't brought forward.

[Jbub]

I'm interested in the blue wire tip too. I've been planning to install an ESU decoder into my GS4 also but haven't had the time. I was planning on just adding some caps for sound drop outs, I didn't know about the issue with them interfering with the lokprogrammer, is there a work around for that or is buying a huge 30 dollar circuit really the only way. I want to do an install on a pair of GP60's also and there is no way of installing the power pak into those.

[RBrodzinsky]

The only work around for the caps is to disconnect one of the leads to them for when you want to use the LokProgrammer.   Most of the time this is not an issue, since I always load and test the sound files into the decoders using the LokProgrammer / LokTester combination before ever putting into a loco.  I even pre-plan any function mapping changes, etc., prior to the install, such that I can use the LokProgrammer to set them as the decoder defaults.  I then use Decoder Pro for any other programming, saving the "default" files, as well as any changes, such that it is simple to reload the decoder if a problem occurs (and ProgTrack reads with JMRI work just fine).  Only if I want to load a new sound file, or update the decoder's default settings, do I need to pop the shell, disconnect the lead to the caps, and use LokProgrammer again.

Some folks even use a micro connector on the leads, to allow for easy connect/disconnect. 

The ESU keep alive pack is really cool.  If you don't turn off the sound, and then kill track power or lift the loco off the track, the loco continues for a couple of seconds. My only concern will be my "dead track" sections on the layout, which are deliberate protection if I don't have the lift out bridge in.  CV113 can be adjusted for the amount of time the charge will last.

[peteski]

Only if I want to load a new sound file, or update the decoder's default settings, do I need to pop the shell, disconnect the lead to the caps, and use LokProgrammer again.
Some folks even use a micro connector on the leads, to allow for easy connect/disconnect. 

You only need to disconnect one side of the keep-alive to take it out of the circuit. You can find some really small single-pin male/female connectors for that.

Please tell more about the dual diode circuit.  I have always wondered about installs where the blue wire isn't brought forward.

The "blue-less" headlight circuit has existed since the 6-pin NEM connector was introduced in the early years of DCC (actually, it goes back to pre-DCC Selectrix days).  The 6-pin connector does not include the blue pin. The solution was to hook up the positive side of the lamp (back then it was incandescent) to either of the rail pickups.  Since the DCC track signal flips polarity many times a second, either rail will be positive for some portion of the time (at whatever duty cycle the DCC signal has). It probably averages to about half the time (50%).  Since the pulses occur faster than the eye's response, and also since incandescent bulbs have thermal lag where the filament stays hot after the power is removed, the human eye did not see any flicker.  Even when LEDs are hooked up that way the flicker is too fast for the eye to notice most of the time.
If someone uses the DC channel 0 functionality (pulse-stretching) on their DCC system, if the above mentioned method is used, the "blue-less" headlight on the  DCC loco will dim depending on the DC channel's throttle speed and direction setting. That is because the duty cycle of the DCC signal is modified to run DC.

But nowadays, several loco manufacturers of DCC-ready locos which use a 6-pin connector solved that problem by generating a "true blue" voltage independent of the decoder. Arnold SW1 is one such loco.   The common positive (blue) voltage on a decoder is obtained at the positive output of the bridge rectifier. Bridge rectifier consists of 4 diodes: 2 to derive the negative voltage and 2 for deriving the positive voltage from the DCC track voltage.  Since we only need to obtain the positive voltage, we only need half a bridge rectifier (2 diodes).  Here is that simple circuit.  It does not show the current-limiting resistor - it can be added on either side of the LED.  This circuit's "blue" voltage is equivalent to the "blue" voltage which is present on the decoder (but it is not connected to the decoder).  To simplify the circuit there are dual-diode components readily available in 3-lead cases (normally used for transistors).  The one I use is a DIGIKEY part # DA3X103E0LCT-ND. It is rated for 80V 100mA (more than ample for driving LED headlights).

[RBrodzinsky]

Cool, thanks. I'm going to add those to my next DigiKey order. I still have 4 (or 8, if I want to replace prior non sound installs) Kato Mikados and an FEF to do.

[woodone]

Why use the blue wire? If you use the right or left rail as a supply you will get 1/2 wave voltage for your LED. It will work just fine. Saves one less wire to fiddle with. Just make sure you use a resistor in line with the LED..

[peteski]

Why use the blue wire? If you use the right or left rail as a supply you will get 1/2 wave voltage for your LED. It will work just fine. Saves one less wire to fiddle with. Just make sure you use a resistor in line with the LED..

You must  have not read my lengthy explanation. The other side effect I noticed with white LEDs is that even if the function that is driving them is in an "off" state they don't fully turn off if your method is used.

[woodone]

I have been using this method for years and have never had a problem. Don’t know what LED’S you are using but I have never seen one the was lit when the function was off. The LED is a diode and will block the back side.

[peteski]

I have been using this method for years and have never had a problem. Don’t know what LED’S you are using but I have never seen one the was lit when the function was off. The LED is a diode and will block the back side.

Believe me - I understand what LED is and how  it works. Regardless,adding a tiny SMD dual diode circuit to the model is not that difficult and the model will be fully DCC compatible in all the different operational modes.  I also run my models in DC mode and that circuit also guarantees that the headlight will light up in DC (yes, I also realize that hooking up the front headlight's positive lead to the right rail and rear headlight's to the left rail would make them work in DC).

[woodone]

This will work in most cases, I work with N scale and there is very little room .
The OP was about an N scale locomotive, and running with DCC.
I have installed many DCC with Sound into this very locomotive and have used this method to reduce the wire count between loco and tender.
Never had a problem.
Never had a LED light up with out being turned on. I use a LED in the H/L,MARS, and number boards.(

[peteski]

This will work in most cases, I work with N scale and there is very little room .
The OP was about an N scale locomotive, and running with DCC.
I have installed many DCC with Sound into this very locomotive and have used this method to reduce the wire count between loco and tender.
Never had a problem.
Never had a LED light up with out being turned on. I use a LED in the H/L,MARS, and number boards.(

Well, our experiences are different. The LED does not stay lit but it flickered faintly. It was a Model-Power 4-4-0 loco and I don't recall the decoder brand (most likely Digitrax). I did not troubleshoot the problem any further - I added the circuit I described and the problem was solved (and the model had a reliable remote-blue source of the voltage). The dual-diode component I use is slightly larger than SMD 0805 resistor. It can be installed in the tightest spot, even in a Z scale loco.

Yes, the original post was about a DCC loco, but that does not exclude me from providing information (which BTW was welcomed) on how to make the model 100% compatible with all modes of DCC and DC operation, while eliminating one wire from the harness - ust by adding a small component.  Nobody is forcing you to use it (but as I demonstrated it, manufacturers are doing it too).

 

[woodone]

Yes, our experiences are different. Yet I still will prefer to use one less wire when possible.
I have installed well over 2,000 decoders and I have used this method many times. In an steamer loco,room is not much of an problem- Diesels are way too tight to cram much more into them but the speaker and a decoder.
Why add a circuit when deleting a wire will do the same thing?
You may want to try what I have used and see it does work has I have noted.
Maybe my room is not dark enough to see the slight flicker?