tender drive DCC fitting.

[Atholl]

Hi,

I have been trying to fit a DCC chip to a (Hornby?) tender drive Britannia loco.

Even with the 3 pole ringield motor brush plate fully isolated at the attachment screws I an getting an earth feedback to the earth brush holder via the armature spindle (shaft).

I am at a loss how to overcome this with the few (small) tools I have.

I will be very grateful for any advice.

Hopefully I have attached photo's of the set up, which does not seem like any Hornby I have traced so far.

Jim.

Edited October 10, 2011 by Atholl

[RedgateModels]

Tricky .....

 

I'm assuming that you have the MKII tender drive that does not have traction tyres on all wheels and relies on the non geared wheels for power pickup.

 

this thread on the old forum details what I did to isolate the chassis from the brush holder

[Atholl]

Thanks Redgate,

You have quite elegantly done what I thought might be the solution - isolating the brush holder from the end plate, leaving no need to isolate the end plate itself.

If I had received no replies I would probably have attempted it off the cuff. Now after your tribulations I know where I am going. And it is going to save me hours of "suck it and see"!

Your pictures show a unit exactly like mine, but mine DOES have traction tyres.

One last question (I hope). IS this a Hornby loco? I bought it (used) as Hornby, but unusually I can find no markings except "SU" on the loco. chassis above the front bogie truck.

By the way, I fitted a chip to a 3 rail Hornby Duchess I had already converted to 2 rail years ago, by ( simply in that case) isolating the rear, earthed, brush holder.

Many Thanks Again, Jim.

[RedgateModels]

Yes, although to be pedantic "Triang/Hornby"

 

just to clarify, the MKII unit has traction tyres on two wheels, the MKI unit had tyres on all six wheels and relied totally on the track feed from the loco - this was only used on the Evening Star loco as far as I am aware. All the Britannias had the MKII with removable tender and power feed from one side of the loco only.

[Atholl]

Thanks again Redgate,

The Britannia (or tender?) is running fine on DCC.

As you said "Tricky". However everything was fine. The main hiccup was deciding that the red wire from the loco. needed to be connected to the black wire from the decoder. However, having slept on that - no problems. Perhaps the most frustrating bit was putting the brushes back in with my clumsy fingers. But I have to admit things like that were easier 50 years ago.

Regards, Jim.

[naugytrax]

All the Britannias had the MKII

Er, not quite all of them. R.552 "Oliver Cromwell" had the tender with 6 traction tires and a permanent 2-wire connection to wipers on the loco drivers. The available tractive effort is quite impressive compared to later versions!

 

My sample has the anonymous chassis with the "SU" marking, like Jim's. I just got it out for a look, and I was reminded that originally the loco pickups only wiped the front and rear drivers. I added wipers for the center drivers, gaining an improvement in electrical connectivity. This might be significant in a DCC conversion.

 

Oh, and I don't think it is "Triang-Hornby". The box that I bought it in (from W&H Models, 9 pounds ninety-five) is marked "Hornby Railways Silver Seal Locomotive" and "Made in Great Britain by Rovex Limited" By the time the Silver Seal locos appeared, I'm pretty sure they had dropped the "Triang" identification.

[ColHut]

Apologies for raising the dead with this. I have an old tender drive Bittern acquired by my son as a gift. It has the Mk II tender drive with pick up on the loco left side and return vis the chassis and axles to the tender right side.

 

Having now seperated the tender chassis from the motor, can I not replace the three Hornby live RH wheels with X1140 wheels insulated lh style wheels and then refeed the output power from the chassis/connector via wipers to the back of the tenders wheels to safely complete the circuit. The DCC chip can then be safely inserted into the circuit between the input wire from the tender connection to motor on one side and the chassis to wipers on the other?

 

 

Regards

Edited September 6, 2016 by ColHut

[ColHut]

Ok wheels purchased second hand for $10 for 4, although I really only need 3. I will wire it up and see how it goes.

 

Regards

 

And it worked fine, completely isolated the axles from the track....

 

And then I realised that the keeper plate was plastic, and the only thing making the body live was a wire connecting one side of the motor to the body. I blush.

 

So by disconnecting that wire I can connect the chip in the usual way, and after re fitting the original conductive wheels on one side, the DCC circuit is complete.

 

Proof that one can re-invent the wheel.

 

Regards

Edited September 7, 2016 by ColHut

[Ozzie Nick]

Hi,

Understand this is a very old post, but I am currently tying to convert this exact same loco. Redgate's link to the old forum seems to be invalid now, and was wondering if either Atholl or Renegat could confirm how you isolated the shaft? I have isolated all screws and the plate itself from the chasis, but cannot work out how to isolate the shaft.

Many thanks!

Nick

[RedgateModels]

4 hours ago, Ozzie Nick said:

Hi,

Understand this is a very old post, but I am currently tying to convert this exact same loco. Redgate's link to the old forum seems to be invalid now, and was wondering if either Atholl or Renegat could confirm how you isolated the shaft? I have isolated all screws and the plate itself from the chasis, but cannot work out how to isolate the shaft.

Many thanks!

Nick

 

You are coming at the problem from the wrong direction Nick, you need to isolate the brush holder from the faceplate.

 

I've done a few now and here's what I do:

 

using a large drill bit remove the end of the holder where it is rivetted to the faceplate

 

 

Then drill out the faceplate so that the smaller hole is the same size as the larger one

 

 

I then use araldite to glue the white plastic part in place and then drill & tap the faceplate to accept two 11BA screws (I use them because they are the right size to fit X04 motor brush holders in place too)

 

 

Hope this helps

[Ozzie Nick]

Thanks heaps Redgate!

I will try today. Appreciate the quick response!

[malc60015]

Hi Ian, thanks for posting the silver seal guide as it is a future project for me when I have rewound a 1970s duchess of Sutherland armature, I have just competed a rewind and made a new commutator for one 70s d of s now I have to sort wiring to enable a decoder to be fitted in the future.  I do like the tender drive ringfields at least you can work on them. 

Cheers malc

[DCB]

Tender drives are easy to work on but in my experience the traction tyres make the track filthy.  We banned traction tyres a couple of years ago and withdrew the last half dozen or so tender drive locos from regular service and noticed a bit reduction in the amount of track cleaning needed.   The old Loco drive Triang Britannia takes the tender drive cylinders and bogie wheels and the driving wheels take Hornby "Hogwarts Castle" driving wheel tyres, and stuffed with lead makes a very nice powerful and reliable loco which does not shed handrails and footsteps when you pick it up, unlike the modern one.