Hornby Class 37 Ringfield DCC Conversion

[Arthur Dent]

Hello folks,

Please be gentle - first post and apologies if this has been asked before.

I have an aged Hornby Class 37 which I would like to convert to DCC by adding a decoder.

I have figured out the following:

It has a Ringfield motor and covered by Service Sheet 210 (URL: http://www.hornbyguide.com/service_sheet_details.asp?sheetid=263)

I need a Hornby Sapphire Decoder (R8245).

What I can't figure out is how the loco is wired up.

It seems that it takes power from one rail in one bogie and power from the other rail from the other bogie.

As such, would it be a simple matter to add a DCC Decoder and, if so, has anybody documented the procedure.

I'm a DCC noob - so any help in "simple-to-understand" Noddy language would be appreciated.

Thanks for reading this post, I hope someone can help/advise.

Cheers

Art

[poliss]

You need to find out what type of Ringfield motor it is. Some need the metal screw replacing with a nylon one.

Instructions on Brian Lambert's page.

http://www.brian-lambert.co.uk/DCC.html#The

 

A guide for installing a decoder can be found here.

http://railsintheroof.blogspot.co.uk/2007/10/fitting-dcc-decoder-to-hornby-class-37.html

[2e0dtoeric]

Hello Arthur - have you got your towel?

Regarding the Ringfield, most of them had one wire running from an insulated pick-up on one axle, and the return was directly though the chassis to the uninsulated side of the wheel/axle.

So - you have to find a way of isolating the motor brush from the chassis, then connecting the decoder to the pick-ups and chassis, and to the motor, but NOT to the chassis, otherwise you will be having an instant fry-up of chips!

If you hunt around the forum, you will probably find a better description, with a step by step procedure to go through.

BUT before you start dismembering the chassis, check on DC that the motor works correctly, and that the brushes and commutator are not worn down. Check also that the magnet hasn't decayed with age, and lost it's pull, or you will find that the motor draws lots of amps, but doesn't work very well.

Again, if you hunt around the site, you will find a place where you can get the magnet restored, and a description of how to replace brushes and clean the commutator.

(Edit for a typo)

 

[96RAF]

There have been successful and very simple conversions of ringfield motors to accept a dvd tray drive motor, but these come in various voltages, diameters and thicknesses, typically you need 25 mm diam with 12.5 mm thick being ok for 4 wheel bogies, but you need a slim 9 mm one for 6 wheel bogies to avoid the centre wheels and these thin ones are usually low voltage so it can be hard to find something suitable.

 

you can also improve the pickups by fitting a twin pickup to the front bogie and solid wheels without traction tyres to the motor bogie along with extra pickups, but this may be outwith your skill set at the moment as you say you are a complete newbie, but I'm sure it wont take long before you are getting in there and fixing stuff.

[Arthur Dent]

First of all, a big thank you to those of you that have replied to my initial post  😀

Still trying to figure out likely difficulties in converting this loco.

Not sure how to clean the motor and/or replace the brushes.  The plastic motor can seems to simply separate to allow access (no clips or screws) but I can't figure out how to get the motor out of the bogie (it looks like it just clips in from above).

Again, any advice most welcome!

Art

[Arthur Dent]

You need to find out what type of Ringfield motor it is. Some need the metal screw replacing with a nylon one.

Instructions on Brian Lambert's page.

http://www.brian-lambert.co.uk/DCC.html#The

 

A guide for installing a decoder can be found here.

http://railsintheroof.blogspot.co.uk/2007/10/fitting-dcc-decoder-to-hornby-class-37.html

Hi poliss,

 

The motor is identical to that shown on the Service Sheet 210 (link below).  There is a single, brown-coloured insulated wire running from the bogie at the non-motor end.  I guessed that the return was through the motor bogie but can't see any electrical contacts.

 

I have a DMM so I can check for continuity.

 

Service Sheet 210 URL (can't seem to post links!): 

http://www.hornbyguide.com/service_sheet_details.asp?sheetid=263

 

Cheers,

 

Art

[Rog RJ]

Thee motor chassis has a couple of lugs, one front and back,  that hold it in place.  Use a small screwdriver to lever the rear? of the motor assembly down to get it out.

[Flashbang]

Hi

If your loco is wired as per service sheet 210b and the Ringfield motor has three or two wires on each side of the brush strips (Silver strips retaining the carbon brushes in place), then simply unsolder all the wires on one side and keep them together. Solder these to the decoders Red wire.  

Unsolder all the wires on the other brush strip and solder them to the decoders Black wire. Cover both in-line joints with insulating tape or use suitably sized heat shrink tubing slid on before connecting together, then once joint has cooled slide the tubing down over the joint so as it covers all the  bare wires and shrink down with the soldering irons barrel not the tip!

Now solder the decoder Grey and Orange wires to the two brush strips.

 

Set loco onto Programming track and set a new address from the 3 supplied.

 

Once ok, place loco onto main line and test under DCC power.  If the loco runs the opposite way to the direction setting on the DCC system reverse the Orange and Grey wires on the motor.

 

 

Note 1; all other decoder wires are Functions and used for lighting control etc and are not used on this loco. Tuck them safely out of harms way or cut them off at the decoder if you're sure you wont  ever need them.

 

Note 2: An older Ringfield motored loco MUST run faultlessly on DC rail power before any DCC conversion is considered. A poor running DC loco will become far worse on DCC! So if its at all hesitant to start or runs poorly service it then retry on DC power. If no better do not convert!

[96RAF]

Here's the circuit as it stands Arthur:

 

Referring to your referred service sheet...

 

The left hand front wheels are live to their axle and via the axles to that metal beam with the wire connected to it. That wire connects to the front terminal on the motor.

 

The right hand front wheels are insulated from the axle and play no part.

 

The back terminal on the motor is connected direct to its frame through the screw that holds the brush retainer on to the frame, which is live through the axles to the right hand side wheels on the motor bogie.

 

The left hand rear wheels with the tyres on are insulated from the axle.

...............................

Converting to DCC:

 

I've summarised the content of Brian Lambert's site for this motor just to give you a brief description of what to look for - so here goes.

 

You must ensure the motor terminals are not connected in any way to the wheels, hence to the motor frame which is live to the track - see later. This state of isolation is essential else you will blow your decoder.

 

You connect the existing wire from the front bogie to the decoder left pickup (black wire).

 

You need to replace the rear metal screw on the brush holder with a nylon one - Peters Spares do them but the thread is wrong so just be careful 'adjusting' it or it will snap. This insulates the motor terminals from the chassis. Check with your meter that this is so before proceeding.

 

Connect the motor terminals to the decoder orange and grey wires. Either way will do as you can adjust later in the decoder CV settings.

 

That leaves how do we get the right hand rear wheel power to the decoder. As the motor frame is live to these wheels and there is a tapped hole at the front of the motor frame we attach a wire from there to our decoder right pickup wire (red).

 

This completes the DCC circuit.

 

...................

 

New brushes and springs. Just remove those brush holder screws and ease away the metal plates and all will be obvious. It is a fiddly job and the bits are liable to fly about so take care not to lose them. People have been known to do it all in a plastic bag.

 

Edit: Further advice from others as I was typing.

[96RAF]

Forgot to add you should snip off that capacitor item 15 on the ref'd service sheet.

 

@Brian

According to the service sheet its a one wire loco.