Motor isolation

I have done something similar. Both frame halves contacted each motor half. I use Kapton tape and nylon screws.

Kapton tape is thin and tough.

I am quite sure the new Roundhouse open frame motors would fit if you ever desire a motor with flywheel. They snap right into a plastic motor holder. My 1998 and 2008 Roundhouse loco's have the motor with flywheel. The NWSL 45 to 1 replacement gears are very nice. They all run very nice with a Tsunami Micro.

Yes, I saw, keep the cost down.

Rich

I hope you don't mind...

This is EXACTLY what I need, so I copied it to have as an instruction sheet!  I hope that's OK with you.

Rafael

I demand royalties!

Absolutely not!  I demand payment for every loco, by the running minute!

Of course it's okay with me!  Why do you think I did the installation now, when I have so many other projects on the shelf?  By the way, on your loco which runs backwards:  If you do this conversion, you can leave it alone.  With the motor isolated, it doesn't matter what the polarity of the frame is (unless you use metal couplers in metal boxes and couple to other similar models).

On replacing motors, gears, etc.:  Yes, there are a lot of ways to improve these models.  My goal for this one is not to make it the best engine ever, just to add a decoder to the model as-is, without a lot of money or time invested.  As such, I wanted to re-use as much as possible.  Besides, with the conversion done as described, it can easily be reversed and all the other improvements can still be done in the future, if you like.

I should have stressed one point.  It is imperative that the ENTIRE bottom of the motor be insulated, from the brush back to the magnet.  If it makes contact with the frame anywhere, you will let the magic smoke out of the decoder.  I don't know how I got away with it - either the decoder has a safety built in, or being temporarily wired backwards saved it, or I'm just lucky today.  I do NOT recommend trying your luck with the same thing.

  "just to add a decoder to

"just to add a decoder to the model as-is, without a lot of money or time invested"

- Ken                

That's my way of thinking too.  I'll worry about improvements later if I can do the basics first!

Very cool!  My issue is I have the entire learning curve ahead of me in DCC - I read one book and did not understand much!  Most of the conversation here goes about a foot over my head.  This is basic enough that at least I can get it.  

Now... programming track.... hmmm.... ??!

Update - The decoder will not fit as shown

As the title suggests, I made a mistake!  There is not enough room behind the motor for a decoder.  Because I had already cut the motor leads short, I was somewhat limited in my options for placement.  There is a fair bit of room ahead of the motor and above the worm, so..

I cut a scrap of .010" styrene, taped the decoder to it, and taped that to the top of the motor so that the decoder fits just ahead of the motor frame.  It's not rigid, but it is well clear of any moving part, and the body now fits properly.

The wires are just snuck through a hole in the frame for now.  I'll route them properly when the new pickup solution is finished.  As always, it is important to check that no shorts were introduced with the modification.  Here's the loco reassembled, just to prove that it actually does fit together.

Any DCC system should have a programming track output.  The power is lower, and will not generally damage an improperly installed decoder.  It also allows programming that cannot be done on the main line.  In my case, I'm using a garden track outside the (as yet unbuilt) roundhouse.  Eventually, I'll put a DPDT switch in the leads, so that it can serve as a normal track or a programming track.

DCC is pretty simple, really

There's not that much to DCC, to be honest.  Like you, I was more than a little lost and confused when I first started thinking about it.  I decided to jump in and just figure it out, so I bought a Digitrax Zephyr, sat down with the manual and a locomotive, and slowly worked through the features.  I had made the rather risky decision to install a sound decoder in a steam loco without having a DCC system (risky because I could not test the installation) and that gave me the opportunity to play with all sorts of CV's.

One thing I highly recommend:  Keep a notebook with a page for each loco.  Write down any CV you change and it's new non-default value.  Of course, it's also handy to include things like the manufacturer and decoder, so you can refer to it for similar future installations.

New Roundhouse

A picture for comparison for those not familiar with the present loco's. Same size frame used for the 4-4-0, 2-6-0 and 2-8-0.

Rich

Hi Ken, DCC really is quite

Hi Ken, DCC really is quite simple. The same  principles apply that are used in DC. Two suggestions if I may. I would replace the metal screw and plastic sleeve with a plastic or nylon screw. Make sure you have a supply for next time. To me it is just too risky and you stated you have fried one already and almost this one. Not for this reason by why tempt fate? Also, I encourage all who have a PC or laptop to GET DECODER PRO! No need for sheet of CV's and notes, etc... It will make DCC that much easier and fun.   

Steve 

DCC controller

I use the NCE Power Cab and set it to program track, first. I then flip the switch to power the program track. I had mis-wired a decoder. The red and orange wires looked almost the same under the lighting I was using and swapped them. Right away, the Power Cab let me know there was a problem. The Micro Tsunami was not damaged. That could have been a $90 error.

Rich

Been there, done that.

DCC is simple when you understand the basics of DCC. Until then, it is not plug and play. I remember my humble beginnings.

Having a basic knowledge of digital devices is a good help.

I belong to at least twenty MRR forums and see a lot of new people jumping into DCC with little knowledge and making sometimes, costly mistakes. Some make assumptions based on DC which many times are different when using DCC. I have lost track of how many have smoked a decoder or burned out a LED because they thought it worked like a light bulb.

I see many discussions about using a PC with the controllers and many have issues. Not to scare you but there is a learning curve. Remember how you felt when you first learned how to drive and how you drive now is a lot different.

Rich

gonna have to save the entire thread...

Lots of good info here!

Needs and desires, if you like

There are a lot of good ideas being offered up here.  There are a number of ways to go about converting an old loco to DCC, and there are even more ways to improve it.  One of my goals with this thread, though, was to show what can be done without adding, replacing, or modifying anything unless absolutely necessary.  There are people who have a very limited budget, for whom the advice "go buy the new motor and put it in" simply will not work.  There are also people without easy access to a hobby shop or parts suppler, for whom the advice "replace the screw with a plastic one" is not practical.  If there were simply no way to make it work, that would be one thing, but if I can make the model work with the original parts, I like to at least try that first.  That is the reason, for example, that I did not go into the modifications I am making to the bottom plate to allow the model to pick up power through all 8 wheels.  I also did not go into modifications to the pilot truck.  While they will improve the model (at least in my opinion) they are not critical parts of getting an old loco running on DCC.  I will be commenting on them in the future, however, when I have them finished and working properly.

I don't mean to put down good advice.  Having a supply of various nylon screws would be nice.  I searched long and hard for one, but I could not find one in my stock of parts which would fit, so I had to resort to more complicated methods.  Replacing the motor would improve the operation of the model, as well as making the conversion a lot easier.  Unfortunately I do not have the budget at the moment to go replacing perfectly serviceable motors.  I did check to see if any of the spare motors I have on hand might fit, but none would without a lot more work than just using the one in the model already.

As for Decoder Pro and JMRI and so forth:  I want them.  I have no doubt that they will improve life.  I even moved my computer into the layout room specifically for that purpose.  But...  See the comments above regarding budget.  The programs are free, but the hardware is not.  I have to chose between a locomotive and decoder or the computer interface.  One I can put to work on the railroad, the other I can do without fairly easily.  So, for others in my situation, if you cannot use Decoder Pro for the time being, keep good notes on a sheet of paper, or in a spreadsheet!

stupid question...

But, if I install TCS M1 decoders in all my MDC old timers:

1) can I run them on DC or will it fry the chip?

2) can I buy any brand DCC system?

3) Do i have to wait to have a "DCC test track" to install?  Does this mean I have to build the layout before I can do the conversions?

I said they were stupid questions..!

There are no stupid questions

Yes, you can.  All the power only decoders I have seen (and the vast majority of sound decoders) are dual-mode.  That means that they will recognize a DC voltage on the track and respond to it.  In fact, I have heard of people who do not have a DCC layout who still install decoders, because of the ability to tune a motor's response to a specific voltage, direction, etc.

Also, as far as I know, one of the DCC standards is that DC will not damage any decoder (provided that it is withing the normal voltage range), even if the decoder will not do anything useful on DC.

That's another key provision of the DCC standard developed by the NMRA.  Any DCC system should operate at least the basic functions on any decoder-equiped locomotive.  TCS, for example, does not make a DCC system, but their decoders work perfectly on my Digitrax system.

No and No.  You do not have to have a programming track.  In theory, if you follow the instructions above and do not have any shorts between the motor and frame, the engine will work.  If you don't want to invest in some sort of DCC system, at least buy or use a multi-meter and verify that there is absolutely no connection between either rail and either motor brush.

The programming track allows you to do two things, though.  First, it lets you test the installation and verify that you have not made a mistake that can damage something (if you can program and read the address on the decoder, you should be safe).  Second, it lets you change the decoder's address and various features - start voltage, peak voltage, voltage curve, back-emf, etc.

And you do not have to build the layout.  You can use a simple DCC system (or even JMRI and a DCC-USB computer interface) and a simple length of track to program an engine.  The engine does not move significantly during programming (it may jerk a little as the motor is pulsed).  If I were on a really tight budget and did not already have a DCC system, I'd look at one of the computer interfaces.  I think they have programming outputs that do not require a booster, meaning that the total cost would be in the $70 range (assuming you have a computer you can use for the purpose).  Or, if you have a friend with a DCC layout, get him to help you program your locos.

Good...it's a "go ahead"

Good...it's a "go ahead" then.  

I have several computers I can use.  I assume the processor speed is not a big deal. My first homebuilt is probably around a 600 Mhz machine, and I have two more that are around 1.5 Ghz...  Will any version of Windows work?  I think two have XP, one probably still has 95!

Check out JMRI

Rafael,

You don't even need Windoze!  JMRI works on Linux, Mac, etc.  Check it out at http://jmri.sourceforge.net/ and see for yourself what you think of the software.  I have installed it, but do not have the hardware to interface with the layout yet.  I know that a lot of people think very highly of JMRI, though.

Tsunami in the Old Timers

I have a "what I did" about putting a Tsunami in the old MDC "Old Timers" at:

http://www.pacificcoastairlinerr.com/1905/roundhouse_sound

I never added loco pickups but here is a method on a Bachmann Old Tyme 4-4-0:

http://www.pacificcoastairlinerr.com/bachmann_4-4-0/wipers/

Thank you if you visit

Harold

Harold, Thanks for

Harold,

Thanks for posting.  Your site and techniques have been an inspiration to me.  I knew I'd seen that Kadee coupler and circuit board trick somewhere - that's exactly what I'm doing to my engine.

For those who have not seen his site, Harold has a number of very interesting "outside the box" ideas, and some good stuff on making small steam locos run well.  I highly recommend it.

Question about NWSL regear kit

I was just thinking about something..  The NWSL regear kit for these models has brass gears, right?  I can see that being a problem.

I cannot think of a good, reliable, simple way of completely isolating the locomotive frame from the rails.  I suppose I could line the axle slots with styrene or paper, but then I'd have to open the slots a little or turn down the axles - neither of which I can do well enough to keep the model running properly.  So I have accepted that the frame will be the same polarity as the right hand rail.

The motor frame has a similar issue.  If I could get an insulated bushing, as used on the top brush, the frame could be isolated from the brushes.  However, I cannot easily get said bushing, so I have accepted that the motor frame will be the same polarity as the bottom brush.

Now, here's my problem.  If the gears are metal, and the frame is metal, and the axle the gear runs on is metal, then the gears would be live, just like the frame.  But if the motor frame is metal, and the shaft is metal, and the worm is metal, then the worm gear is also live, just like the motor frame.  Would I not then have a short between the worm and gear?  Surely somebody has had this problem, or installed a decoder and re-gear kit and can say definitely that it is NOT an problem.

Finally got it running

It took long enough, but the need for more motive power and some friendly nagging finally got me to finish getting this locomotive running.

I like to have all wheels picking up power, plus I don't have a tender for this engine yet.  Those two factors combined to make it necessary that I improve the pickups on the model.  I replaced the bottom cover plate with a new piece made from circuit board, by using the original as a pattern.  I then made wipers from Kadee centering springs.  To keep things simple, I bent the whiskers out, cut away the majority of the "bottom" of the spring, and soldered the remaining piece to the circuit board with each whisker brushing against one driver tire.  I then cut a groove in the cover plate, leaving the mounting screws on the side that was originally picking up on the model, through the frame.  As I mentioned above, I could not get the frame completely isolated from the driver tires, so I simply accepted this and kept all the connections on the right side.

As you can see in the photos, I ran the red and black wires through the open space in the frame, beside the gears.  I still need to glue or somehow bind them to one side, but that's easy enough to do.  I also ended up bending the inside whisker on each spring so that it rubs the tread instead of the back of the tire.  Because of the off center location, it was not making good contact and was occasionally getting caught in the driver spokes.  The outside ones, since they rub against the outside of the wheel, do fine where they are.

After testing on the programming track and tweaking the fit of a few things, I tried to run it.  Let me tell you, brass tires (especially old ones) are a royal pain to clean.  It took a little time and a paper towel soaked in lacquer thinner, but I got it running fairly well.  The motor is incredibly noisy, so I might look into one of the new ones if Athearn will sell it to me as a separate part.  But at least it runs, and aside from the noise it's not bad.  It ought to do even better with pickups on the tender as well.

As a side note, I replaced the 0-80 slot head screws used as crank pins with hex head screws and washers.  I'm not sure, but I think the 0-80 screws fit into the same holes as the factory press-fit plastic crank pins, and they look a lot better.  I had to file the heads of the screws thinner to clear the main rods, but that was a fairly simple job.

Yes, the headlight wires are still exposed.  Until I finish the model, or at least figure out how I am going to build and detail it, I'm leaving them long, and there's no room to tuck them inside comfortably.