# Converting 1976 flying Scotsman to DCC



## ..TrainMaster.. (Nov 7, 2015)

Hey there fellow train technicians. I was wanting to know if anyone knew how to or knew a link to information on how to convert a 1976 flying scotsman from DC too DCC. Unfortunately my scotsman is not DCC ready so it does not have a removable DC plug port like most DCC ready locos would have. I also ended up getting a hornby R8249 4 function digital decoder before i discovered my train was not DCC ready. Anyone got any advice?


----------



## Cycleops (Dec 6, 2014)

From the age of the loco I would think it's a tender drive. Should be a fairly straightforward operation. I don't know if you've installed many decoders previously but once the motor is isolated from the frame it should be plain sailing, if indeed it needs isolating. Here is a video from you tube which may help you: https://m.youtube.com/watch?v=6gXoiUkP3gE

If you could post some pictures of the drive that would help.


----------



## ..TrainMaster.. (Nov 7, 2015)

Hey friend. Nah the loco is driven from inside the loco itself. What do you mean by isolate the motor? This would be a first time decoder installation process for me. So I got know idea what or how to go about it


----------



## Cycleops (Dec 6, 2014)

I had a Hornby loco in the eighties and it was tender drive, guess yours was prior to them adopting this configuration. 

By isolating the motor I mean sometimes it is wired through the chassis. If it is you need to isolate it otherwise the decoder will be spoiled, so you need to check this. Just look at the wiring from the motor, trace it back and see if at some point a wire is connected to the chassis. It may not so wired in which case your job will be easier. As I said post some pics of the disassembled loco and drive that would help you proceed.

Here's another video of a tank of a similar vintage to yours which may help you: https://m.youtube.com/watch?v=Ad9X0VRaNok I couldn't find any of the engine you mention but the principles are the same.

I did find this from a company that does DCC conversions which looks like it could apply to your loco:

"This is an interesting conversion. The loco is an old Hornby Scotsman with standard 3 pole motor built into the live chassis. The motor terminal connected to the chassis is simply isolated by cutting the insulation collar to the insulated brush in half and using it to isolate both brushes".

So it looks like the motor needs isolating.


----------



## ..TrainMaster.. (Nov 7, 2015)

My loco motor setup looks like this



















https://m.facebook.com/photo.php?fbid=1120276157991219&id=100000265355585&set=rpd.100000265355585&source=49&refid=17&ref=bookmarks


----------



## Cycleops (Dec 6, 2014)

The picture is just so small I cant tell much from it. Can you identify the motor brushes? As that quote I gave you it says there is a plastic insulator on top of both brushes, it says to cut this in half so you use the other half to insulate the other brush.

In the mean time please post a better pic with a close up of the motor installed and one just showing it removed.

I can see it better now. The brushes will be about where you are pointing.


----------



## Cycleops (Dec 6, 2014)

I've seen the facebook pics now which are clearer. Looks like that wire on top is grounding one of the motor contacts to the motor frame, cant tell which one but it will need isolating. Once you've done that you can proceed with the decoder install. The wheel current picks up are: Right side going to the red decoder wire and black going to left. The grey and orange go to the motor contacts, doesn't matter which but if it runs backwards just swap them over. The other wires will be for lighting.


----------



## DonR (Oct 18, 2012)

On a loco of that age you should do a stall test to determine
which decoder to buy. Older locos often draw too much for
the typical decoder and will wipe out a 1 amp decoder.
Decoders are available with higher ratings.

Before you disconnect the wires from the motor note which
tab was connected to the right rail feed. The decoder instructions
will tell you which wire to connect there thus the
loco will go forward when you push forward button.

After the installation and before applying power do a
short test. Set a multimeter to ohms. Probe each motor lead with
the other probe on the the frame. If you get a reading find how
that happens and correct it.

Don


----------



## Cycleops (Dec 6, 2014)

That's a good tip of Don's about checking for any shorts before putting it on a powered track. It's to check the motor connections to the decoder are not touching anything else and the motor is properly isolated. Let us know how you get on. Btw you'll need some small diameter heatshrink to insulate the connections. Mount the decoder on a piece of double sided foam tape.


----------



## ..TrainMaster.. (Nov 7, 2015)

Oh... so what I'm trying to achieve is removing the earthing from the locomotive frame and making the current earth through the right power rail via the decoder? 
My scotsman is earthen through a tension spring that holds the brushes in place. One side of the tension spring is already insulated in tubing so it can't touch the brush it sits against(which I guess counts as isolating it?) So in theory if I do the same with the other side and run all the circuitry through the decoder it should work?


----------



## ..TrainMaster.. (Nov 7, 2015)

Ok... very minor issue... which I will get to soon. First up, I have disconnected the + wire leading to the wheel pick ups ( and yes there is only one) and soldered that wire to to the red wire of my hornby 4 function decoder. Soldered the orange/bronze wire to the right hand brush terminal. And the Grey wire to the left hand brush terminal. That leaves me with the black return wire for the right hand rail and a blue common v+ wire. Now here lies my issue. This locomotive has no return lead that would normally go to the negative side of the track. The motor would normally earth through the motor casing. So... what should I do now?


----------



## ..TrainMaster.. (Nov 7, 2015)

Cycleops said:


> That's a good tip of Don's about checking for any shorts before putting it on a powered track. It's to check the motor connections to the decoder are not touching anything else and the motor is properly isolated. Let us know how you get on. Btw you'll need some small diameter heatshrink to insulate the connections. Mount the decoder on a piece of double sided foam tape.


I wonder if I could get away with making a homemade copper pick up for the absence left hand one. According to my research the hornby x03 motors never had a return line on that make of motor. They all earth on the motor frame. Cause I need a return line to complete the decode installation


----------



## Cycleops (Dec 6, 2014)

Sounds like you'll need to make a pick up for the left (black) pick up, mount it somehow and insulate it. If you've insulated the spring that holds the brushes that should be ok. 

The blue common wire is for lighting, as is the white and yellow.


----------



## DonR (Oct 18, 2012)

I think you are saying the the 'black' or left rail electric
contact was through the wheels to the loco frame. If that
is the case simply attach the decoder 'return' to the
frame. Just be sure that none of the motor tabs make
contact with the frame. There may be a screw into
the frame that you could use to secure the wire.

My older Bachmann GP30 uses a split cast metal frame that
was the conduit for both left and right rail current. I made
a plastic 'wedge' with the decoder input wires on either side
pressed against the frames. It works perfectly with no
loss of power.

Don


----------



## Cycleops (Dec 6, 2014)

The left side pick up runs through the frame and contacts the motor in DC mode. I always understood the golden rule was to isolate the motor otherwise shorts could occur. It is not a split frame like the Bachmanns of old. My old Atlas has a similar arrangement where one of the contacts ran through the motor frame, it needed isolating and the running straight to the motor.


----------



## DonR (Oct 18, 2012)

Cycleops

You are right, the motor should be totally isolated from the frame.
What I was saying was how to use the frame for the 'return' side
of the Decoder input. The frame is electrically a part of the left
rail on this loco from what he said,
so I'm saying use that for the decoder return and not have to go to
the bother of adding wipers to the left rail wheels.

Don


----------



## ..TrainMaster.. (Nov 7, 2015)

DonR said:


> Cycleops
> 
> You are right, the motor should be totally isolated from the frame.
> What I was saying was how to use the frame for the 'return' side
> ...


Sweet. I'll make this change and then do an ohms test then let her flying


----------



## Cycleops (Dec 6, 2014)

Let us know how it goes.


----------



## ..TrainMaster.. (Nov 7, 2015)

Cycleops said:


> Let us know how it goes.


All wired up. Runs fine on the DC track. Now I need to give her a run on dcc track set up


----------



## Cycleops (Dec 6, 2014)

I cant stand the tension! Let us know as soon as poss!


----------



## ..TrainMaster.. (Nov 7, 2015)

Cycleops said:


> I cant stand the tension! Let us know as soon as poss!


Haha ok will do


----------



## ..TrainMaster.. (Nov 7, 2015)

More my question. For the auxiliary functions, lights, smoke etc... to ground them do I just earth them to the motor frame as I did with the decoder?


----------



## DonR (Oct 18, 2012)

No. Do not use the frame for any electrical connection except the
left track feed to the input of the decoder. The decoder wires must be
your sole source of on board power for lights etc.

Usually the blue output wire of the decoder is common PLUS.
You will have to check the decoder manual for the color wire
that is a decoder switched negative output for lights, etc.

Be sure to check the decoder manual to determine if the
smoke unit goes through it. It may draw too much current.

One experienced with the smoke unit could tell you if it
can be connected across the raw DCC track current. jIf it
can be, you would use the frame for the left track current
and the red wire from the right track wheels.

Don


----------



## ..TrainMaster.. (Nov 7, 2015)

Good news fellow modelers. With your help and a lot of time and research the flying scotsman is now safely DCC
Many thanx to you all


----------



## DonR (Oct 18, 2012)

Good Show.

Don


----------



## Cycleops (Dec 6, 2014)

That's great. If it hadn't we'd have all looked like proper fools!


----------

