DC to DCC Conversion

[Rangerover]

You really don't need the light board, in fact some modelers remove them to make room for decoders/speakers. Also you can purchase some Digitrax Z scale decoders, which are the size of a dime that you solder in without the light board, they are equipped with back emf and come with complete simple to follow instructions. I have 3 (plug in, but you can cut off the male plug and solder in) of these installed in BLI Blueline loco's HO scale and they work great and easy install. They can be purchased at Tony's Trains or Litchfield Station which have discount prices, do yourself a favor and don't buy the cheapest decoder's you can find. The digitrax DZ 125PS is selling under $25.00 and (the DZ 243PS with 4 functions under $35.00, your cab rotating light or a mars light would be connected to the extra functions which you need for those functions), the directions are included again with the decoder.

Here on Z scale decoders, (for Z,N, and HO) click this on and read the information.
plug in:

http://www.digitrax.com/prd_mobdec_dz125ps.php

solder in:

http://www.digitrax.com/prd_mobdec_dz143.php

Hey I was petrified to open the shell and install my first solder in decoder, it took me about 2 hours, now after the first, if the motor is already isolated, it takes 20 minutes to 1/2 hour and that's in a steam loco.
Just do it, if you have a problem just come here, that's what I do.
Welcome and Good Luck, above all have fun! Jim

[Yampa Bob]

The NCE decoder board replaces the existing light board, even comes with new LEDs. As a package, the current limiting resistors on the new board are probably optimized for the included LEDs.

A tiny Digitrax decoder might be hard wired in the available space, but don't forget the lights. With the light board gone, and by not using the NCE replacement board, there won't be any mounting brackets to support the lights. Also, using a standard decoder will require installing current limiting resistors.

Remember we're talking about diesels, not steamers. Everyone should download and read the PDF instructions so you will see how the lights are mounted on the board.

Again, the final decision is up to Mathew, just wanted to mention all the facts.

I'm rather fascinated by the NCE boards, think I'll order a couple myself, the decoders in my GP40s are very noisy. 

Regards.

[Rangerover]

Remember we're talking about diesels, not steamers.

Bob

I simply mentioned the  steam loco's only as an example of the time involved, they are after all a bit more time consuming than diesel, at least I found it so. Probably only because I like steam and take my time with them. But I've only converted 7 loco's so far to DCC and consider myself a beginner and learning too. Any loco whether steam or diesel, which isn't DCC ready but that can mean anything, takes longer depending on if you need to isolate the motor or hog out some of the weight for decoder/speaker installs.

I converted 2 old Atlas diesel F units to DCC which had 12 volt bulbs, so I didn't need resistors, leds do need a resistor which is no big deal and as per jward's link, the modeler cut the light board so as to use it as a mounting bracket, it's quite simple. Easier doing that than hogging out the weight.

Also I believe the OP has a light board similar to what I had in my Atlas just copper strips with no resistors or electronic gizmos, with the light wires simply soldered to the strips.

When and if the bulbs burn out I will install leds with resistors.

In the future as I am converting to DCC, some with sound, I will be replacing the bulbs with leds, just makes more sense since I got them apart.

Since the OP is installing an oscillating/strobe light of sorts on the roof of his loco, there is no place on the light board to solder or operate that addition, he still would need the 4 function decoder for the install and to operate it. And the common blue wire for the lights on the decoder would have to be used for the installation.

Mathew, read the links provided by all, you will find, like most of us have, that it's all quite simple, but there are all kinds of techniques modelers use to achieve the outcome. I played with DCC only 4 years and only been installing/converting some of my own favorite loco's to DCC for the past 2+ months. With all the jargon it does get confusing, but the more I do, the easier it gets. I spent a lot of time(4+years) on threads like this during that time reading and learning and visiting and downloading to folders pdf files, and now I find I only needed a few resources plus following the directions that come with the decoder or calling the manufacturer for specific directions if problems arose. Believe it, it's all rather simple, after I did my first one, I remember shaking my head and saying "is that all there is to it".
Jim

[Rangerover]

I'm rather fascinated by the NCE boards, think I'll order a couple myself

Bob, thanks for that link about NCE decoders and light boards. I just spent a couple hours looking and reading on their web site. I haven't read many reviews about them or on forums or threads. I like the idea that you can program and remapp them provided you have the system to do that, I'm glad I got the PR3 and JMRI program more than ever. I'm going to order one just to see how they function and if they hold up.

Thanks again, Jim

[Yampa Bob]

I think we are all guilty at times of "not seeing the forest for the trees". Until Mathew posted this thread, I could only base my comments about upgrading the DC diesels on what installers and others have reported.

Of course, being an Empirical Skeptic and non-conformist myself, when someone says it "can't be done", I get more determined to do it anyway.    The word "can't" is not a usual part of my vocabulary.

For my own enlightenment, and to be in a better position to advise others on this topic, I ordered not only the NCE decoders, but also a Bachmann DC version of a GP40, so I can do an actual upgrade.

I also wrote a letter to NCE support for more detailed information. If the decoder meets the claims, they might be missing the boat by not mentioning the DC to DCC upgrade possibilities for an increased market potential.  This might also increase sales of Bachmann DC diesels to those who prefer installing their own decoders.

Thanks to Mathew, we may see new horizons here.  Also thanks to Jeffery Ward, if he hadn't mentioned NCE, I would not have remembered the BACH-DSL board. As Jim Banner says, we learn from each other. 

[pdlethbridge]

As a decoder installer, I've stayed with the least expensive decoder, the dh 123. After doing more than 20 upgrades from DC to DCC on athearn, Lifelike, Bachmann and brass imports, both steam and diesel, they all have their own types of problems. I have found though that steamers are much more of a problem because of the wires between the loco and tender. Using 30 or 32 gauge wire makes the install go pretty good but you have to watch out for shorts and insulate every potential area.

[Jim Banner]

While I agree with PD that there are advantages to sticking to one or two types of decoders, and mostly do that myself, I think the simplicity of the NCE Bachman DSL decoder makes it a better choice for a first time installer.  Added to that simplicity is a great set of instructions, making it quite difficult to go wrong.

I guess this is a case of me suggesting he do one thing while I do something different.  So be it.

Earlier, Bob was worried about how to mount the headlights if you used a standard decoder.  A trick I have often used is to keep enough of the ends of the lighting board that I can mount the lights on them, or leave the original lights mounted on them.  By nicking the copper traces, I can easily disconnect the lights from as much or as little of the original circuit as I want.  In a few cases I have removed all the other components and all the unused copper traces, cut a square hole in the middle of the board to drop a tiny decoder into, and put the lighting board back in place.  More often, it is possible to leave the lighting board in place and slip a tiny decoder up into a fan or dynamic brake housing.  But let's not wish that on Mathew on a first attempt.

PD, one trick I like to use when doing steam locomotives is to put the decoder in the locomotive rather than the tender.  That way I need only 3 wires between the locomotive and tender, assuming tender pickups and tender light.  That is only half of the usual six wires and they cause less than half the trouble.  With sound decoders, you may not save any wires but you end up with more room for a larger speaker in the tender.  But it can be harder to find enough room for the larger decoder in the locomotive.

Jim

[Yampa Bob]

I have modified a couple of light boards, just didn't want Mathew to realize the "dark side of installs" until he gets his feet wet. 

To paraphrase "Yoda", fear leads to suffering, suffering leads to anger, anger leads to a huge hammer. 

[MathewWorley]

Hello everyone,

     Im in aww that my question has possibly created a new chapter. Not only does it sound like my question has helped others and stirred up new curiosity, but it may have helped a few companys in the process. I wonder how much my checks will be?? just kidding lol.  I hope that this thread has helped others like it has me and it sounds like it has and more. I hope to start or attempt my install(s) soon, just waiting to get the cash cow from the barn and the time to sit down and goin from there. I also wanted to thank everyone who has given advice and input to help me upgrade my fleet. Ill be leaving the thread up to see how far it goes and to refer back to it.
                                                                                 ---Mathew---

[Yampa Bob]

Hey Mathew,
We're having as much fun as you are. Suggest you place this thread in your favorites folder for recall. It may be awhile, but I plan to upgrade a DC diesel myself out of curiosity.

You've heard the expression, "Out of the mouths of babes". We get lots of ideas from new members. Some of the questions are quite thought provoking.

Keep us updated on your progress, and remember if it works out ok, be prepared to be the teacher the next time someone asks about it.

In the words of Larry the Cable Guy...."Git 'er done" 

[WGL]

I am not sure if Mathew has N-scale or H0-scale GP-50s so here are some thoughts on Digitrax decoders for both scales:

N-scale -  DZ123 (low cost) or DZ125 (includes BEMF)

H0-scale - DH123 (low cost) or DH163 (includes BEMF and four extra function outputs)

BEMF stands for Back ElectroMotive Force, which is the voltage generated by a motor when it is turning.  This voltage is measured by a BEMF decoder and compared to a voltage that represents the speed you set via your throttle.  If the motor is going too fast or too slow, the decoder makes the required corrections.  In this respect, it is rather like cruise control in an automobile.

Where BEMF control really shines is at low speed.  With most locomotives, you have to set the throttle to about 30% to get the locomotive to start.  Then it runs, but often faster than the slow crawl you would like.  But with BEMF, you set the throttle to say 1%.  If the motor does not start, the decoder ups the voltage until it does.  When it does start moving, the decoder will reduce the voltage before it moves too fast.  The result is a locomotive that starts smoothly and runs smoothly throughout its speed range, including the all important low speeds.  This is ideal for switching freight cars and just as great for pulling a passenger train out of the station without spilling a single bowl of soup in the diner.

Jim, if I had installed BEMF decoders (which I didn't know about until I read your post) into my BlueLine DC with sound locomotives, would they then have momentum, instead of lunging at start & stopping suddenly? 

Also, does momentum decrease the top speed of locomotives?  I wonder because my 4 Bachmann locos with DCC onboard have top speeds of about 80 or less, while my 2 BLI DC with sound into which I installed DCC decoders, have top speeds of 100+.

[jward]

blue line are supposedly very good locomotives, with excellent low speed control. if your is lunging, something is wrong. maybe you have something in the gearbox that would be causing this? do you hear a clicking sound when you run the locomotive?

matching speed between decoder equipped locomotives is a simple matter of adjusting the top speed of the faster locomotive. cv5 adjusts the maximum voltage.

[Jim Banner]

WGL, the answer to that is a deffinite maybe.  It depends on why your locomotives jack rabbit starts and stops.  But before we get into that, let me ask you a couple of questions.  I am assuming you are running on DCC.  What system do you use?  And what sound decoders did you install (make AND model?)  I assume we are talking about sound and motion decoders, not sound only decoders.  Some of them already include BEMF control and all you have to do is turn it on or program it.  Others do not have it but there are work arounds.

Just to make sure we are on the same wavelength about momentum.  There are two CVs that adjust momentum, CV3 for acceleration and CV4 for deceleration.  If they are set to zero, then the locomotive will react to the throttle directly - turn it up to a new setting, the locomotive immediately speeds up to the new setting.  Turn it down, and the locomotive similarly slows down immediately.  With momentum turned on, you can drive your locomotive more like you would a real train.  When starting off from a dead stop, you can crank your throttle up to full power right off the bat.  But instead of a jack rabbit start and reaching full speed immediately, your locomotive with momentum will (or should) start gradually and accelerate up to speed.  You may not want full speed even though you applied full power but what you can do is turn the throttle down to an appropriate level once your locomotive is going the speed that you want.  By increasing the momentum during acceleration (by programing higher numbers into CV3) you have have your train react as if it was heavier.  That is, it will accelerate more slowly, even if the power you apply is the same.  This is not a whole lot different than driving a real diesel.  The engineer puts the throttle in run 8 (full throttle) and leaves it there until his train reaches the desired speed, then backs it off to maybe run 3 or run 4, whatever he thinks will keep it at that speed.  The same with deceleration.  The higher the deceleration momentum is set, the heavier your train seems to be and the longer it takes to stop.  With a high deceleration setting in CV4, it takes quite a lot of skill to stop your train exactly where you want it, just as it takes a lot of skill in the real world to stop a 100 car train exactly where you need it.

Acceleration and deceleration do not always work quite the way you would like them to.  When starting from a dead stop, you might apply lots of power and then have to wait before your train starts moving.  This is because your locomotive does not necessarily start at one percent of maximum motor voltage.  It might need 25 to 30% of maximum before it will start.  And it will take some time before you reach that voltage when you start off from zero with acceleration momentum applied.  But as long as the train starts smoothly when it does start, we can correct the waiting problem by increasing the start voltage programmed into CV2.  If your locomotive took 25% of maximum voltage to just start, then you program 64 into CV2 (because 64 is 25% of 255, the maximum you can put in CV2.)  Then when decoder calls for 0 speed, the voltage applied to the motor is zero.  But when it calls for an increase of speed, the motor voltage immediately jumps to 25% of maximum voltage and the locomotive immediately starts moving at minimum speed.  All the in between speed steps are automatically skipped over.

Way back at the beginning of the last paragraph, I said that as long as the train starts smoothly when it does start, we can correct the waiting problem.  But what happens if it does not start smoothly?  Poor mechanical design, wear, lack of lubrication, and throttle mismanagement are the four most common causes of jack rabbit starts.  ("Throttle mismanagement" is just a fancy term for cranking the throttle up too fast when you are not using momentum.)  By using acceleration momentum as discussed above we can eliminate throttle mismanagement.  And by lubricating and maintaining the locomotive, we can usually make it start more smoothly.  Poor mechanical design still shows up in old train set locomotives but mostly today we are dealing with five pole, skew wound motors, flywheels and precision molded gears.  So we can expect smooth starting and what we get is quite good, but still not perfect.  What we need for the ultimate in smooth starting is a little man sitting inside our locomotive with his hand on an auxiliary throttle and each eye on a gauge.  One gauge tells him how fast the motor is supposed to be turning and the other gauge tells him how fast the motor is actually going.  His job is to adjust this throttle to keep the two gauges matched.  If he does his job well, all we should see from the outside of the locomotive is the slight change in speed as the decoder steps through its 128 steps between stop and full speed.  The little man is available to all of us and his name is BEMF.

BEMF control will not solve all the problem with a bad locomotive.  As a test, I installed one in a  Tyco locomotive from a train set bought in the late 1960s.  Before the install, I cleaned, lubricated and test ran the locomotive on dc.  It ran about as well as it did 40 years ago, smoothly and reliably at half throttle and above.  But it took almost half throttle to get it started, and then it went from zero to 50 in about 6 inches.  With a BEMF decoder installed and tweaked (a very long process in this locomotive,) it would start at 1% throttle (on a Digitrax DT400 throttle) and would speed up along with the throttle but to get it to do this, I had to set the decoder gain so high that the speed was "hunting," that is, jumping up and down in a most annoying manner.  I had visions of the little man having apoplexy as he tried to match his gauges.  Later I tried the same decoder in an older Athearn locomotive, about 30 years old.  On the dc test, it had a much smoother start, but still with a bit of a jump from zero to maybe 10 mph.  Similar locomotives with with non-BEMF decoders had similar jumps.  With the BEMF decoder installed, it had silky smooth starts and I was able to start and stop it four times per tie running down the line.  Basically, the BEMF decoder turned this good locomotive into a great locomotive.

But as with most good things, BEMF decoders have their limits.  Being unable to deal with inadequate locomotives is one of them.  Running in consists is another.  If you put two BEMF equipped locomotives together, you will often find one of them spinning its wheels as the decoder applies full power to get it up to speed while the other shuts down and drags its wheels in an effort to slow down.  It is like that first locomotive has a gauge that reads actual motor speed just a little bit too low, so the little man in it jams his throttle fun open to try to get the speed up.  The reverse is happening in the other locomotive - that little man sees his locomotive being speeded up by the first locomotive and so applies the brakes.  The solution would be to take away their glasses so that they cannot read their gauges quite as closely and some decoders effectively do that, letting you turn down the BEMF gain at the push of a button for when you put them in a consist.

Decoders do not reduce top speed when you use momentum.  CV5 sets top speed unless you are using a speed table.  Off hand, I would say that CV5 is correctly set in your Bachmann locomotives if they are intended for passenger service and a tad high if they are for freight only.  In real locomotives top speed is usually set by the gearing between the traction motors and the axles, 80 mph max for passenger service and 60 mph for freight (varies by railroad.)  You can bring the top speeds of your other locomotives down to more reasonable speeds by adjusting CV5.  Start off with a value of 255 and keep dropping it by 50 at a time until you get about what you want.  You can do the final adjusting in steps of 10, then 1 if you want an exact value.  Just remember that 0 and 1 in CV5 do not give you zero speed, they "shut off" CV5 so that it has no effect on maximum voltage.

Hope this gives you a better idea of what is going on but I apologize if all it does is put you to sleep!! 

Jim

[WGL]

Jward, no, I don't hear a clicking sound when I start my BlueLine locomotives.  My experience with DC locomotives, like the Lifelike F7 with my first HO train set, is that they start & stop quickly.  Maybe better DC locos operate more smoothly.

Jim, thanks for your detailed explanations.  In my BLI DC with sound Heavy Mikado, having its own sound decoder, I installed a Digitrax DN143IP motion decoder, because it was at the top of the list of recommended decoders in the Mikado's manual.  I have EZ Command.  I turn the throttle very slowly, hear the Mikado wake up, turn more & then see it move.  The best I can do is minimize its lunge to avoid uncouplings.  It can pull 16 cars at about 120 mph.
When I ordered the BLI SD40-2, I also ordered a Digitrax DN143IP for it.  When I received them, I saw that the manual listed a Digitrax DZ143PS as the top choice.  The SD40-2 reacts like the Mikado:  after it awakes, more throttle makes it move, & it wants to lunge.  It pulls 14 cars ranging in length from 40' to 75' at 100 mph, & it probably isn't completely broken in yet.
You lost me a few times, but I did not get sleepy.    Now, I know that top speed & momentum are not connected.  I've ordered The Dcc Guide: How to Select and Use Your Command Control System by Don Fiehmann, & I may buy a Digitrax Zephyr, if only for programming.

Bill

[jward]

i have had my zephyr for 5 years now and i love it. it had the knob control like a dc power pack, so it was pretty intuitive for me to pick up. i have also operated on layouts with nce and mrc systems, and both use a thumb wheel instead of a knob for speed control. i find them a bit harder to use.

about the lunging effect. it has been a few years since i ran a decoder equipped locomotive on dcc, but i seem to recall that it did not run smooth, requiring about half throttle just to get moving, then taking off like an old tyco locomotive. when i made my earlierr reply, i had forgotten about running that locomotive on dc.....

this locomotive was a model power metal f7. before anybody bashes model power, let me say i am very impressed by this locomotive. it has a speed curve similar to the much more expensive stewart f7s, and it will pull the paint off the walls as well.