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Fitting decoders to Tri-ang locos


StartingAgain

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I have recently rejoined the model train bug after a 30 year layoff (family, job etc but now on pension). My loco are basically Tri_ang units but also a Wren unit.

 

I was under the impression when they were all boxed up all those years ago that they were in "good" condition. Imaging my shock when I found they were actually in poor condition. However I have picked the best out and have had a number of motors (X04) rewound and new magnets fitted. Having a working background of PLC and Airconditioning Control I decided that I wanted to go the DCC route. To that end I have built my own DCC system from a design shown on the Web and after a number of false starts, I have now got the system up and running. I recently bought a new DCC Ready Loco and fitted a decoder (Hornby 8249) so that I could at least test my DCC system.

 

After querying the right type of decoder for my refurbished Tri-ang units I was advised to start with a TCS T1 decoder mainly because of the current required by the X04 motors. I have now recieved two T1 decoders from the UK and an ready to install them. The question I have is regarding the correct way to wire the track pickup wires (Red & Black). The loco metal body forms part of the return circuit so is there an "earthy"side on the decoder? Having examined two of my locos I see that the pickup springs are not consistant i.e. one loco has the pickups on the left hand wheels whilst the other loco has the pickups on the right hand side. I realise that the default direction can be changed in CV29 but is there a "proper"way to wire the track wires? Are there any other pitfalls that I should be aware off?

 

Regards

 

Gareth

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As long as you ensure that the motor is completely isolated from the chassis/pickups, then the default is that the red wire goes to the right-hand pickiups (and the orange wire goes to the corresponding motor terminal). There is no 'earthy' side to DCC since the signal is effectively (but not really) AC.

 

Adrian

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Adrian

 

Thanks for the reply.

 

When we talk about the right hand side would that be when looking from the front of the loco?

 

Gareth

 

That would be the right side if you were driving the loco. As you pointed out, if you get it wrong it is trivial to fix in CV29.

 

The TCS documentation should have a diagram of the wiring.

 

Adrian

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Hi

Conversion of a Tri-ang loco is quite straight forward, but the loco MUST be a good runner on dc powered rails before conversion is considered.

You state this is the case, so the conversion process is as below. This is a direct copy and paste from my web sites DCC page.

 

Having removed the loco’s body, view the chassis from above and on most older Hornby/Tri-ang loco's a ‘V’ shaped spring can be seen along the top of the motor, this retains both motor brushes under tension. One side has a slide on insulated sleeve. Locate and remove the push fit connector that’s located between the insulated sleeve and the actual motor brush curved upper part. This is normally a simple pull off fit and has a black wire soldered onto it which runs down to one side of the wheel set. Cut off the black wire where it’s soldered onto the connector. Discard the connector. The black wire will be used later.

 

Strip around 12-15mm of wire insulation (16/02 is ideal) and use the insulation to insulate the opposite side of the ‘V’ spring where it touches the brushes top or use a similar length of heat shrink tubing. This means now that both sides of the ‘V’ are insulated from the brushes. Next solder the Orange wire from the decoder onto one motor brushes top section and the Grey wire to the opposite brushes top. Be careful not to damage the insulation – slip a small piece of Paxolin or other heat resisting material between the brushes top and the insulated ‘V’ to prevent the insulation melting while the soldering iron is heating the brush/wire joint. When both are soldered visually check that the brushes carbon blocks are touching the motors commutator and there is no pull on the brushes from the attached wires.

 

Now slip a short length of heat shrinkable tubing over the black wire (removed earlier from the insulated side of the brush) and then solder the decoders Black wire to this. When cool, slip the tubing over the joint and apply a little heat to shrink the tube to form a good insulated joint. Finally connect the Red wire to the central screw that holds the ‘V’ wire in place by undoing the screw a little, stripping approx. 10mm of insulation from the red wire and twisting up the strands to make a solid wire then wrap this stripped end clockwise around the loosened screw. Tighten the screw to grip both the wire and the ‘V’ spring.

 

Place the loco onto the Programming track and check that the decoder can be read , normally its factory preset set to 3. If all is ok then programme as needed.

 

Once programming is completed test the loco on normal DCC operation. In the event of the loco running in the opposite direction to the controllers setting (e.g. reverse when forward selected) unsolder the two wires on the brushes (Orange and Grey) and reverse them or add one to the value in CV29.

 

When reassembling the loco body ensure the area chosen for the decoder’s final position is well insulated. Remember that the chassis is live and will cause a short circuit and destroy the decoder it if it’s not suitably insulated. This can be carried out by applying insulating tape to the area of the decoder’s location and then holding the decoder in place with double sided adhesive pads. Make sure decoders wires are taped clear of any moving parts too.

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Many people suggest using one of the quality more meaty decoders for the older locos as they can draw quite a lot more juice than the newer ones.

 

The old Hornby catalogues used to give an ampage rating for the models which most of the X04's style seem to be about 1A.

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Many people suggest using one of the quality more meaty decoders for the older locos as they can draw quite a lot more juice than the newer ones.

 

The old Hornby catalogues used to give an ampage rating for the models which most of the X04's style seem to be about 1A.

 

Most people would rate a TCS as a quality decoder!

 

T1=1.3A continuous, 2A peak

 

Keith

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Thanks Guys

 

The original wire (brown) from the pickup strips is extremely stiff and has a mind of its own when I try to reroute it to connect to the decoder harness wire so it will be changed for a softer wire.

I am a little bit concerned about the reliability of the pickup system on these old locos but I suppose that is to be expected given tha they are all 30 years old.

As I said at the beginning I was advised to use the TCS T1 decoders because of the current rating. Also my locos are basic in that there are no existing lights (except a Flying Scotsman which has a firebox pea bulb installed) to be controlled so a 2 function decoder is ok.

 

If I have an further problems I will come back.

 

Again thanks for the feedback

 

Gareth

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Thanks Guys

 

The original wire (brown) from the pickup strips is extremely stiff and has a mind of its own when I try to reroute it to connect to the decoder harness wire so it will be changed for a softer wire.

I am a little bit concerned about the reliability of the pickup system on these old locos but I suppose that is to be expected given tha they are all 30 years old.

As I said at the beginning I was advised to use the TCS T1 decoders because of the current rating. Also my locos are basic in that there are no existing lights (except a Flying Scotsman which has a firebox pea bulb installed) to be controlled so a 2 function decoder is ok.

 

If I have an further problems I will come back.

 

Again thanks for the feedback

 

Gareth

 

Hi Gareth

Just a quick observation, it may not apply as I don't know when they were changed but:

Do the locos have the old type tension locks made of metal? They may be continuous with the chassis, which of course has one side live.

If so replace with plastic otherwise if two locos meet coupling to coupling there will be a short.

 

Keith

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Hi Keith

 

Forgive my ignorance but what are tension locks? I think all of my Tri_ang locos have metal couplings as shown in the attachment. If all of the locos are wired the same ie the pickup wheel contact is on the righthand side is it still a problem if I have a coupling to coupling contact?

 

I have just installed a TCS decoder into one of my units (Flying Scotsman -model R850/5) and it works a treat speed wise. it is also runs noticibly quiter that when in the original DC mode. I haven't fitted the cover yet as I want to check everything is 100% first.

I haven't cracked all of the CV programming yet. The only additional connections is for the pea bulb for the firebox indication. I have programmed CV49 (value 33) and used the white and blue wires for that function but at the moment it is not working. I did test the bulb prior to installingthe decoder so it is hopefully finger trouble on my part.

 

Gareth

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Keith: the coupling problem happens when the locos meet nose to nose. Or if you hook 2 diesels together with the power bogies mating.

 

And it's a problem with DC as well.

 

I thought that was what I was saying in a different way.

 

Keith

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