Loco overloading DCC Select

[Tommy-1214182]

Hey everyone, I've just bought a second hand DCC Select from Rails of Sheffield and hooked it up to my track. I also bought a new decoder for my Hornby class 92, however whenever I place the loco onto the track I get the overload warning. I don't get the warning when the loco isn't placed on the track or even when the controller isn't connected to the track. I'm hoping this will be an easy fix. I should also mention that the purple wire on the 8 pin decoder isn't connected to the chip.

Many thanks, Tommy.

[Going Spare]

The Hornby ringfield-motored class 92 also featured directional bulb lighting. If your loco is that type rather than the more modern can-motor/led-lit version, the load of current-hungry motor and lighting may be more than the controller can handle? What is the R-number of your loco?

[Chrissaf]

Tommy,

For some reason your post was held back for image approval, but there was no image. So not sure why your post didn't instantly appear. If you did try to include an image, then you must have done something wrong in your method used to post it.

In answer to your question.

Firstly with regard the purple wire. The wire being 'floating free' is totally normal. The purple wire is a function wire [for example to power a cab light or some other LED locomotive accessory] it is floating free because it is the 9th wire on the decoder and the decoder plug only has 8 pins so there is nowhere for the purple wire to terminate on the plug.

If not used, the end of the purple wire should be insulated and coiled up and stored out of harms way within the loco body.

Now back to your main issue. If just the act of placing the loco on the track triggers the 'Overload Warning' then the loco has a short circuit on it. There is no 'easy fix' for this. It requires access to a multi-meter to measure resistance and a methodical diagnostic testing approach to be used to focus on where in the loco the 'short circuit' is being created.

In the absence of a multimeter there are some basic diagnostic checks you can do.

Firstly unplug the 8 pin plug of the decoder from the 8 pin socket and leave the 8 pin socket empty [i.e do not replace the previously removed socket blanking plate]. Put the loco back on the track.

Does the Select still trip. If it does, then the short circuit is on the wheel wiring side of the socket. If it doesn't, then the short circuit is either on the motor side wiring of the socket or the decoder itself is faulty.

Test two.

Replace your decoder with the decoder 'blanking plate'. Also disconnect the DCC Select controller completely from the track and re-instate your DC Analogue one [it is assumed that you used to operate with DC prior to buying the Select]. Does this loco now run correctly under DC Analogue power. If it does, then this indicates that the decoder or its installation in the loco is faulty.

But before consigning the decoder to being faulty, one other thing to check and confirm. Your post infers that you used to run it as an Analogue DC layout and you are trying to upgrade it to Digital DCC. If this is the case, and you are using Hornby branded track components. Have you replaced the original Hornby track power connector with a Digital DCC one. The DC Analogue track power connectors contain a capacitor that can shunt some of the DCC Select current output, such that adding the additional load of a loco to the track can flip the current drawn from the Select into the tripping zone.

The DC analogue track power connectors can be modified to become Digital DCC friendly by opening them up and cutting out the capacitor. The image below gives details.

This connector capacitor removal modification should be performed on any the following Hornby products if used on your layout:

R8206 Power Track

R602 Power Connector

R8201 Link Wire [both connectors].

As this is your very first post and my reply is a long one with an image. Please do not use the 'Blue Button' to try and reply. This 'Blue Button' is not a 'Reply to this post' button. To reply, scroll down to the bottom of the page and write your reply text in the 'Reply Text Box' at the bottom of the page. Thank you.

[Chrissaf]

Addendum to my last reply:

Going Spare posted whilst I was still typing mine. If his Class 92 assessment is correct and you have an early locomotive with a 'Ringfield' motor, then it is assumed that you 'hard wired' the decoder in as I doubt that the loco had a 'DCC Ready' socket.

Ringfield motors can be converted to DCC but they are not straight forward. If you do not use the optimum method, you can create a 'short circuit' in addition to any high current issues that G.S has indicated with regard to the loco having bulb lights etc. Ringfield motor conversions are not really suitable for the basic Hornby R8249 decoder and need a different brand of decoder with a higher current rating.

If you were to come back and confirm the loco R number and/or motor type and whether LEDs or Bulb lighting is included in the loco, then further advice can be given on what is the optimum conversion methodology to use.

If your Class 92 loco is a 'DCC Ready' loco with a socket, then follow the guidance in my original reply.