Anyone Converted Airfix N2 To DCC

[Smudge617]

Hi Everyone

I have an Airfix N2 Loco which I would like to convert, but as they're not the X03/4 or Ringfield style motors, I have no experience as to the best way to achieve this. (One contact is via the top cap from the weight, the second contact is through a type of prong at the bottom on the other side of the chassis). Has anyone converted one before and what is the best way?

[Fishmanoz]

Hi Chris, I don’t have details of this loco to hand, but let me give you the principles to be followed for conversion as this may help:

• you must connect to track power on both rails.
• in general, this is done via pickups in contact with the wheels or via the chassis through a wheel and its axle. More modern Hornby locos use pickups on each side. Older locos often use pickups on one side and a wheel/axle/chassis on the other
• there must be no connection between the power pickup from the rails and the motor. Any such connection will blow a decoder instantly.
• where one side of the power comes via the chassis, some form of isolation between power and the motor will be needed. This may be achieved simply (think X04 and insulating both sides of the brush retainer spring) or may be more complex (think Ringfield where the LH brush retainer spring must be isolated using nylon screws etc)
• once isolated, remove all wires connecting from pickups to the motor (and discard any suppression capacitors etc).
• now connect track pickups to decoder red and black wires (doesn’t matter which way around) and decoder orange and grey to the motor (if these are wrong way around, the loco will run the opposite way to expected, fixed by reversing the connections)

That’s all there is to it. And note that part of this may be achieved by installing a decoder socket rather than direct soldering of the decoder into the loco.

Trust this helps. Please come back with any specifics for the N2, including photos if possible.

[96RAF]

I think this type of motor may be the one that requires insulated top hat bushes for the brushes. I am sure it has been covered on the old forum before now - somewhere - the text may be found but the associated pictures may be lost.

Or it may be similar to this Prairie with an Airfix version of the X03/4 motor.

Or this pannier tank

https://platform1mrc.com/p1mrc/index.php?threads/dcc-conversion-of-airfix-pannier-tank.2639/

[Smudge617]

Thank's everyone, Fishmanoz I'll take some photo's this weekend `as I try and get this done, I've learnt the hard way to always fit a harness.

Thanks also 96RAF the videos were helpful but they are for the X04/3 motor and I was looking for a solution to connecting the bottom brush without taking the loco to pieces.

So it looks like I will have to remove the weight and try and solder directly onto at least one of the pickups (ideally both, but I'm still very much a novice at this and I don't trust myself to remove the wheels as well), trim the excess that makes contact with the motor on the one side and insulate it, I can solder one wire from the decoder onto the copper strip that runs to the bottom brush cap, I'm also thinking of using the top contact by drilling and tapping the weight, insulate the contact and use a nylon screw then soldering the harness wire from the decoder to that, I don't really want to solder directly onto the top brush cap unless I have to.

If anyone can think of a better way, please let me know (also if I'm making a pig's ear of trying to do it this way).

Thanks.

[Fishmanoz]

We need Son of Triangman (SoT) in here. He will know exactly how to do it.

And sorry, descriptions not doing it for me until I see photos or someone finds a service sheet.

[Smudge617]

My apologies, I should have done this in the first place, it's not getting power to the motor I'm having difficulty with, it's getting power from the pickups, and I'm just not confident enough to take the chassis apart any further than removing the weight.

[96RAF]

This is your current path.

You need to figure a way to insulate the chassis contacts from the motor contacts, then splice in your decoder as normal.

I would bend the chassis contacts clear of the motor and solder my decoder wires to them.

You can ditch the suppressor.

[Fishmanoz]

I think I understand it now. And Rob’s got it I think but I’d put it a different way.

Am I right that there are pickups contacting the backs of the driving wheels on each side, not just one side? Then is there continuity from those pickups through to the top spring clip from one side (where Rob has his red wire in the photo not the diagram) and the lower spring clip on the other side (where Rob has his blue wire)? Then when you mount the motor, I’m assuming either the brush holder or the suppressor contact (one only of each at the top of the motor, and the other the bottom) are press fit contacts to those spring clips?

If so, then Rob is right you must bend each of those spring clips such that they no longer contact the motor when mounted. Now you can solder decoder red and black to the bent spring clips. Then decoder orange and grey go to the brush spring holders. The best soldering points will be the suppressor connectors, not the holders themselves. And yes, unsolder and discard the suppressor first.

It would be good to double-check after bending the spring clips that there is no stray connection from the motor to the pickups when the motor is mounted (any such connection will destroy the decoder). Use a multimeter to ensure there is an open circuit from each motor connection to the wheels, the pickups, the chassis and the spring clips.

Does that make sense?

[Smudge617]

Yes Fishmanoz it did make sense, thanks to 96RAF and Yourself I managed to get it done, as you can see, not pretty, but it works, so I'm happy. I did end up reversing the top contact as it was vibrating against the bodywork and made a lot of noise. Also I did mess it up, damaged the worm gear somehow, so needed to source a new gear, found a few, that might (hopefully fit) so ordered a few different ones. But thanks again for the help and advice.

[Fishmanoz]

Hey Chris, thanks for the feedback and glad you got it done.