Class 155 Sprinter to DCC

[rogiefalls]

Can somebody please help me with this problem; I am in the process of changing over to DCC and would dearly love to fit decoders to two Class 155 BR Sprinter DMU’s, one is the R2108  Regional Railways Metro Train and the other is R2162A Provincial Railways, both run “as new” I have removed both bodies and the two motors look identical. The Hornby service sheet gives the motor number as X8680.

                   

Hattons are advertising the R2162A and say: “DCC compatible but no socket. Ringfield motor (standard)”  The wires on the motor are both red and go to front and back wheels, there is also a black wire loop (is this for lights?) soldered to the front red wire..  This will be my first “conversion” and I would be most grateful for any help with the wiring and the most suitable decoder to use (I have 2 Gaugemaster DCC26 OPTI Decoders, would they be up to the job?) I have spent a couple of says browsing and can find no information at all. 

 

[Phil S]

The colours of wiring used in commercially assembled locos cannot be relied on to identify their purpose - the only guaranteed method is to use a multimeter and test it yourself!.

 

When working on any locomotive, it is a good investment to buy yourself a multimeter, and learn how to use the basic resistance/continuity, votltage (ac/dc)and current (ac/dc)measurements.

Any additional features might be a benefit in the future, but are not required, and might increase the price 8-).  Multimeters can be bought from about 5GBP and that is less than the price of a decoder!!

 

If the loco does not have a dcc-socket, then some soldering will also be required - so a good pair of wre cutters/strippers, and a soldering iron with a FINE tip will be needed (and solder ).

 

With the meter set to resistance or continuity modes (continuity mode often has a 'beep' when it finds a low resistance ie, continuity).... 

With the Loco on an isolated  length of track on your workbench - identify which wire goes from the 'Right' rail (facing 'forward')  to the motor, and which goes from the 'Left' to the motor.  (The motor will show about 10-20 ihms resistance, a wire =0).  If the loco picks up from more than 1 bogie/wheelset, there may be MORE THAN 1 WIRE connected to each rail.

 

ALSO It is always a good idea to check by placing a 9V PP3 battery onto the rails, that tthe loco runs in each direction, and any lights included work correctly in each direction.

(THIS CHECK should work on both ANALOGUE (unfitted locos) AND DIGITAL-DECODER FITTED locos - regardless of their number - UNLESS the owner has disabled DC running)

(A useful test to try if buying a 2nd hand loco at a swapmeet - take your own 9V battery, and a single piece of track in case not all the wheels pickup power)

 

TO CONVERT TO DCC: BOTH SIDES of the motor MUST be isolated from the track supply ... ie the 2 wires identified above need to cut / diverted to go via the decoder....

Check for NO CONTINUITY between track and motor .... I would also check to see if / what parts of the LOCO CHASSIS are connected to either motor or track ... and take note !

 

ONLY 4 WIRES need to be connected to get the MOTOR to work ... the additional wiring will be for the lighting which may be present. (Therefore it can be good to start with a steam loco with  no lights)

 

Using the 'standard colours' for 00/H0/N... Right TRACK = RED,  Left TRACK = BLACK     and  

                                                                   ORANGE is decoder-output to MOTOR 'right' (the connection which WAS the right rail, but is NO LONGER)

                                                                   GREY is the decoder output to MOTOR 'left' (the connection which WAS to the left rail, but is no longer.

(Other colours are used for G Scale)

 

NOTE that if Orange and Grey are connected the other way around, this is not a fatal problem !

- the train will simply 'go the wrong  way' and can be changed by an ODD number in CV29 instead of even, or, since you are soldering the wires ... simply swap them and resolder.

If the 'Red' and 'Black' wires were wired the wrong way round, again this is not a 'fatal' problem .... but he train will go the wrng way when used on DC/analogue with the deocder fitted ..

.. best to swap the wires over when testing before replacing the body etc.

 

HOWEVER if the motor is NOT fully isolated (no continuity once the wires are cut) OR 'Red' / Black is connected to the motor, this WILL PROBABLY be FATAL to the decoder (and possibly motor).

 

Some generic things to watch for: Hornby RINGFIELD - SOME of these motors used a screw to connect one side of the track to a motor terminal. Some have a short wire link which can be removed.

If you have the screw-connection type, it needs to be isolated: I bought nylon screws of similar size to replace the metal screw to do this. 

Manufacturers are required to fit suppression capacitors to analogue locos - but their function is usually replaced by components on the decoder, and so these may be removed. Bachamnn often have 3 capacitors ... one hidden below the motor and connected to the chassis.

 

I recommend geting a small pack of 'heat-shrink sleeving' to slide over the wires you solder  (slide them on BEFORE you solder, and then move them well away from the where the joint will be)...

then after soldering, and the joint has cooled .. slide them over the joint, and heat them with the soldering iron ... they will shrink down onto the join and seal it.

 

ADDITIONAL WIRES: If these are present on your deocoder: If they remain UNUSED - trim off the exposed ends, and tape with insulating tape.

 BLUE is the Positive wire, and common to ALL the lighting.  White, Yellow, Green, Violet** are 1st, 2nd, 3rd and 4th in sequence:  Forward LIght, Reverse Light, Extra1  Extra2 by default

where F0 tirns on/off Forward Reverse, and either F1, F2 or F3 and F4 (depending on decoder) will turn on Green and Violet respectively.  

 

  **9 pin or loose wire on 8-pin decoders

 

Some modern decoders are designed to drive LEDs DIRECTLY with a low voltage/current - BUT MOST ARE NOT: therefore ANY LEDS (or Microbulbs) used MUST have a series resisitor in the loop between Blue, the LED, and White/Yellow/Green/Violet wires.   It is quite possible that the method by which the manufacturer made the NON_DCC VERSION lighting is DIFFICULT to convert to DCC style .... in the case of your Class 155, compare the lighting circuit boards as well !!!

[rogiefalls]

That's a whole lot of information Phil for which I thank-you very much. I have copied your reply and will be "having a go" on Sunday morning. I have already got (in anticipation) the tools etc that you suggested. Once again thank-you for such a detailed answer