Hi Yves
The best I can do is refer you to the parts diagram.

http://www.bachmanntrains.com/home-usa/dwg/dwgs/H833X-IS001.PDF

It appears the LED either plugs into the front or has wires leading to the inside. If you can remove the shell, you should be able to see how the LED is connected.

Hope this helps, others more familiar with the loco may comment.

Regards

I haven't worked with resonant circuits for 30 years, and only vaguely remember that a positive reactance implies inductive, a negative reactance implies capacative. If I refer to the formulas I get one of PD's headaches. 

When I first learned that Bachmann used noise suppression circuitry on the DCC  board, I just assumed the capacitors and inductors created a resonant filter to cancel out the noise and never gave it further thought.

We often advise others to clip the capacitors if they experience erratic performance, but inquisitive minds might be asking "Why am I doing this?"

I think the title mostly applies to us old timers who have spent most of our life working toward retirement. Many of you grew up around trains, but just too busy with work and keeping the wolf away from the door to be involved in model railroading. Unfortunately, I was not around trains during my life, and only became interested in them 3 years ago. (My, how time flies).

For those of us who are retired, and those who will retire in 40 or 50 years, and are or will be going into their "second childhood" at some point, here's a rather thought provoking question.

If you could live your life again, start all over, what era or area would you have preferred to really experience railroading to its fullest?  This is for all modelers, there is no age restriction on "dreams".  The 1800's? early 1900?, early steam or transition era?, narrow gauge in the West?...dream away and share your thoughts.

I was born in what I consider the perfect generation of time, have seen technology slowly develop, and now expanding rapidly. I'm fairly content with my position in time, just had to study furiously to catch up on the history and current technology.

I had a brief infatuation with steam, but I do enjoy the colorful and powerful representation of modern diesel.  I guess I "dream" of being just 10 or 15 years younger, to see what lies ahead, and to have a little more time to enjoy my new found hobby.

Ok, uncover your "time machine" and dial in your destination.

My layout is also an oval that represents about 50 miles point to point between Craig Yard and Phippsburg transfer station, with imaginary line to Denver. Locos will eventually be all diesel except for my wife's vintage steamers/excursions. Actual table size at present is 42" X 86", thought of expanding, but we don't really want two tracks. 7' fiddle track on my side will be a program track and extra car storage.

Hehe, you funny. 

I have two - 4 way USB hubs, which will accomodate 8 - 1 or 2 Gig flash drives. Every few days, all my data gets transferred /updated from the HD to the flash drives.

One drive is devoted to railroad information such as PDF files and photos.  If I'm away from home for even a day, like on a trip to Denver, the drives go with me in a small storage case.

Josh, when you get back up, suggest buying a hub and couple of flash drives. Yeah, I know about the monster portable HD, but don't like it all in one basket.

Walmart has PNY 2 gig flash drives for only $10.

Rusty,
Ok, you can have the Jeep, I want the LVT for trips to Denver. That should compete in the road rage contest.   

I think all the names mentioned are pretty "famous" among modelers. From the "Urban Dictionary":  "When you have achieved fame enough that your name can be found on Wikipedia".  Heck, they named a railroad after me.

I might amend to: "When you're famed enough to be known to a recluse Cowboy". Familiar, famous, popular, well known, es todos mismo.

Stephen,

Thanks for the reminder.

I have that book (#12407 by Mike Polsgrove) great projects and information. A "must have" for every DCC modeler.  I also have the following companion books:   Kalmbach #12412 Basic Wiring for Model Railroaders by Rick Selby, #12207 Easy Model Railroad Wiring by Andy Sperandeo, and #12417 The DCC Guide by Don Fiehmann.

The four books have everything "you wanted to know but were afraid to ask". 

For those who prefer "ready made", I have been suggesting this handy resistor substitution box, has many uses. Grab a bag of miniature crocodile clip jumper wires from Radio Shack for test connections.

http://www.cs-sales.net/rs400.html

Timothy,
That would be "Half-track", which might also apply to some of my posts.  

Rusty,
I think that is a picture of a "Water Buffalo". http://en.wikipedia.org/wiki/Military_vehicle

Thanks Jim
An easy way to illustrate "inrush current" is to consider an ordinary 100 watt incandescent light bulb.  If we divide 100 watt by typical 110 household voltage, we get .9 amp current draw, However that is the current draw for a warm (actually hot) bulb when lit.

I measured the cold resistance of a 100 watt bulb, about 10 ohms. 110 volts divided by 10 ohms equals 11 amps of current, but only for a fraction of a second until the filament heats up. That innocent appearing bulb can suddenly become a 5000 watt "detonator" at peak inrush current.

Now you know why a light bulb usually blows when you first flip the light switch, with a "pop" that will scare the you know what out of you. I've seen some trip a 20 amp breaker, and actually explode, which is why you should never use open bulbs in a potentially explosive environment such as a lighted garage. Ever walk into a closed garage and smell gasoline vapors from a lawn mower, or from gas cans not tightly sealed?  We keep all mowers and gas cans in an unlighted storage shed.

I know some modelers may say: Multimeter? I don't need no "steenking" multimeter!  That's fine, just plan on stocking up on decoders and bulbs because sooner or later Mr. Murphy will pay you a visit.   

FWIW, "Murphy's Law" consists of two parts.
1.  Anything that can happen will happen.
2.  Anything that can be screwed up by someone will be screwed up.   

It depends on the age and circuitry of your locomotives. Older "DC only" locomotives usually have 12 volt grain of wheat bulbs that don't require current limiting resistors. If the lights are directional (headlight or taillight that are lit in the direction of travel) there is a small circuit board (light board) with 2 diodes.

If the locomotives are "DCC ready" with a socket to plug in a decoder, then two conditions might exist: 1. The bulbs are 12 volt, again no resistor required, or 2. The lights are LEDs, in which case current limiting resistors have already been installed on the printed circuit board  by the factory.

Some modelers prefer (or find it necessary) to remove the board and "hard wire" the decoder. In this case if the lights are LEDs, then resistors are required. Most LEDs require a minimum 560 ohm resistor in series to limit the current to 20 milliamps (.02 amp)

This page has lots of information about lighting and LEDs:
http://www.members.optusnet.com.au/nswmn1/Lights_in_DCC.htm

More information with helpful pictures. At the bottom are links to other pages of electronic information:
http://www.kpsec.freeuk.com/components/led.htm

A close visual examination of your lights will determine if they are GOW (grain of wheat incandescent) or LED (Light emitting diode), refer to pictures on the above page. Suggest adding above links to your favorites folder for reference.

I might also mention that a handy item for electrical testing and troubleshooting is an inexpensive digital multimeter. Here is one at a great price, every modeler should have at least one. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90899

TIP FOR ALL. Here's a handy way to test (out of circuit) LEDs with the digital multimeter. Set the dial to "Diode", symbol looks like a small black arrow). Touch probes to the LED leads, observing proper polarity, and LED should glow brightly. The diode position provides 3 volts dc from the internal battery. I always connect the probes both ways in case I have made a mistake in polarity.

Easy formula to determine resistor value:  Supply voltage (12 volt typical) minus LED voltage (3 volt typical) divided by .020 (LED maximum current typical) equals resistor value.

12 - 3 = 9 / .02 = 450.....standard resistor value is 470, suggest 560 for safety.

Regards

Hi Abe,
When I tried installing a Digitrax DH123 in a Bachmann HO 2-8-0, speed was somewhat erratic over the throttle range. Rather than clip the capacitors on the board, I switched back to a Bachmann brand decoder.

In another Bachmann 2-8-0, I removed the pc board and hardwired a DH123 decoder, it ran great.

You didn't indicate the brand/model of your N scale locos. If they are Bachmann, you may have to clip any noise suppression capacitors existing in the loco. I'm not familiar with Bachmann N scale to know the circuitry, perhaps Jim can advise you on this matter.

Regards.

Paul,
Consider yourself lucky...I could have wrote "the reciprocal of the sum of the reciprocals of the individual resistors,  or the product of 2 resistors divided by the sum". I started to but I know you prefer pretty pictures.   

Thanks Jim,

Have you ever determined the approximate total equivalent resistance of the loco / decoder on the program track?

Members of some discussion groups have reported using anywhere from 22 ohms and upward to do the job. A few even reported successfully programming Soundtraxx decoders without the PTB-100 booster.

For inquisitive minds that want to know what the heck we're talking about.

http://www.electronics-tutorials.ws/resistor/res_4.html

Thanks 

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(Test)
http://www.bachmanntrains.com/home-usa/board/index.php/topic,9599.0.html

Jim,
I posted the full URL to my thread above. The hyphen makes it break even in IE, so apparently no need to "tiny" forum topic URLs. I am surprised that today's webmasters don't realize spaces create the dreaded %20 fillers.

I liked your idea of a switch for the resistor for frequent use. I just showed the basic concept. I have an ancient resistor/capacitor substitution box, gosh I can't even remember when I got it but glad I didn't sell it.

The Tiny Urls load just as fast as the original for me, even on my dialup. The site says "Never expires". I think it's a great free service.