Bachmann N Class - non-DCC ready

[Ian Abel]

Whilst I have always used Bromsgrove Models excellent guides as a reference for installing decoders, and was ready to do just that same thing with my recently acquired Bachmann N Class, once I opened the model up, I literally thought "hang on, wouldn't it be nice to re-use the existing PCB?"

 

So here's my contribution, hopefully it is useful for someone.

 

This guide is only useful for the following scenario/reasons;

1) Bachmann N Class non-DCC ready model

2) Using the TCS M1 Decoder (suggested anyway by Brosgrove - and TCS is my personal choice for decoder range)

3) A desire to have the decoder a plug connection at least for the track power side. Two less solder connections.

4) Zero modifications to the existing frame/structure

5) ZERO requirements for any heat shrink or electical tape around wire joins, as there aren't any!

 

Standard procedure, as documented by Bromsgrove, for chassis removal with these notes;

1) On my loco the front screw under the bogie DOES come all the way out, so be sure not to lose this one either. Probably a change of design somewhere along the way

 2) I found the probable cause of body/chassis tight fit is from the motor contacts and wires, gently bending them closer to the side of the motor - and using electical tape on the motor to avoid a short - solved the problem. I found this out as I needed to separate and join the body/chassis several times in testing the fit/suitablility of the PCB board/decoder mounting I was attempting.

 

View 1 - Layout of components

 

 

Visible are the two screws that hold the PCB to the frame, the capacitor, two chokes and track power supply plug.

 

Disconnect the track power plug, and remove the two screws holding the PCB to the frame.

 

View 2 - Board removed

 

 

Unsolder the two wires from the motor contacts and you now have the PCB free to work on.

Carefully unsolder/remove the two chokes, the capacitor and the motor wires, cleaning up the solder side (Back) of the board as much as possible to remove solder.

 

View 3 - Front of Board, components removed

 

 

View 4 - Back of Board, components removed

 

 

The TCS M1 wires will need to be shortened as necessary to help with the install/space issues.

Using double-sided foam pad (3M) mount the decoder on the front of the PCB hard up against the track plug, with wires at the top.

Thread the two track wires, RED and BLACK, through the appropriate holes as indicated on the pictures above, and solder to the PCB at those locations.

Shorten the function wires (I left them about 1 inch long so I "could" use them if need be and/or I move the decoder to another loco) and tape on the front of the decoder with electrical tape.

 

View 5 - Decoder mounting arrangement on PCB

 

 

Re-attach the PCB to the frame with the two screws, plug in the track power, and solder the two motor wires GREY and ORANGE to the motor terminals.

 

View 6 - PCB/decoder mounted to frame

 

At this point it's worth testing the setup, before re-attaching the body. If the loco runs in reverse, swap the motor wires over.

 

Again, this is just provided as an alternative to the already documented mothod.

I just liked not having to do any surgery to the frame, and the fact that it's only two soldered wires rather than 4.

 

 

[RFS]

Bachmann must have changed the PCB board at some time, because mine didn't have the track power plug on the board.  Instead all 4 wires were soldered directly to the PCB, so that had to go. Mine has a Lenz silver mini decoder and it runs very well with that. Previously it had a TCS M1 as recommended, but after a few months' use it emitted the dreaded blue smoke.  It was replaced by TCS but I sent it to Ebay and installed the Lenz instead.

[Stevelewis]

Having  fitted   decoders  to  many  locos  since  I became  involved  with Digital  in'97 (I stopped  recording  when  i  reached 400+),  I feel  that  the  simplest  / most  straightforward  way  to digitize non  DCC ready locomotives,  is  to  simply  remove all on board  pcbs  and  simply   hard  wire a  suitable  decoder  straight fromo  the power in put cables from  the  loco pickups and  to the motor power supply  connections, ( and of  course  lighting connections  if lights fitted)    In accordance  with  Decoder  wiring  protocol.

 

It  should be  remembered  that  the components fitted to a PCB on an  analogue  are  rendered redundant in most  cases and  removal of the PCB  provides  additional  decoder space.

 

As  a  matter  of  interest  many  RTR 0 gauge  locos  such  as  those  from  Bachmann Brass had nothing  more inside  them on delivery  than  2  wires  connectiing  the  pickups to  the  motor,  no trace  of  a PCB!

 

I also  note  the  comment  above  re  TCS decoder failure,   over  the  years  I have  had  very  few  failures  ( unless those I fitted them  for  failed to  inform me which is  doubtful!!!)  But TCS is the brand  I have  had  the  most trouble  with.

[Rustycat]

I followed the suggestion with my Bachmann N Class. I removed the PCB and was left with four wires. Two to the motor (red and black) and two from the pick-up (brown and black).  I connected them to  a TCS M1 chip - orange and grey to the motor and red and black to the track.  Before re-assembly I tested it on my programming track. As soon as the wheels hit the track the motor started running a full speed. No opportunity to program it.  It was like the chip was just a pass-through.  This was a brand new chip.  I have tried to convert a couple of items and have not had much success.  My inexperienced view is that somehow the chip is defective or it somehow fried the minute it hit the track.  All my conversion attempts have been with a M1 chip.  They claim it is suitable for HO, but maybe it not with UK OO.  Any thoughts or suggestions would be appreciated.

 

I have contacted TCS about past problems and their answer is always "you have a short somewhere".

[SRman]

Both of my N conversions used Digitrax decoders - DZ123 and DZ125. Given the choice, I would prefer the TCS M1 but wasn't able to get those at the time I did the conversions. In both cases, I removed the Bachmann PCB completely to give the decoders plenty of room.

I still have a southern liveried N to convert, so this one may well get a TCS decoder installed, when I "get a round tuit".