ColinB

I am wondering if DCC decoder is damaged and is thinking the DCC signal is DC. Trouble is it is not that easy to check as the decoder is hardwired. If you do find there is a fault with the DCC decoder, when you replace it, put an 8 pin socket in. There is plenty of room in these locos for a socket, then that gives you the option of changing between a DCC decoder and a DC header when you have a fault.

You'll be pleased to know Hornby have fixed this issue on the Thompson A2 and the new Merchant Navy, so obviously they do listen. For once, I did use the supplied speaker with both of these models.

I know this is an issue as it has been reported before. If you look at my posts you will see how often than I complain that the Hornby speaker fittings are generally not fit for purpose. I think this one when you screw down the plate to hold it, it is under tension which is not right. What I do is replace the normal Hornby Speaker with a small iphone one available from "Road and Rails". It also sounds better.

I was about to bin it, it was only that nothing else looked damaged that I persevered.

I was recently asked by someone to fix their failed loco that had a LokSound decoder in it. Anyway on further investigation I found two of the input diodes had gone short circuit. It was a LokSound v3.5 decoder with a 100 ohm speaker. Anyway this seemed a bit weird as normally when this happens the diodes fry and you get smoke, but this decoder looked perfect except it put a "short" across the tracks. So I did the normal and asked LokSound if they did a replacement service but it appears it was too old for the cheap replacement option. So I thought I would try fixing it as it was broken anyway. I removed the four diodes that made up the bridge rectifier and replaced it with a small bridge rectifier that I wired onto to diode pads with thin wires. It now works perfectly. I know this is a Hornby forum, but as anyone else had this sort of fault with this decoder to me it seems very unusual.

Thank you 96RAF for the link, it still doesn't tell me that much more but I will just assume it gets it right. My multimeter is a reasonably expensive Fluke, but I am pretty sure although it says it measures true RMS, I think it assumes it is sinusoidal AC.

I am surprised, I have found that tension lock couplings are far superior to NEM ones, although they don't look so nice. If you are going to change them, I would go for the magnetic ones where you can get a far closer coupling.

So how is the RRamp meter different to say the RMS measured on a Fluke multimeter? I Googled it but basically all I can find is that it measures AC. I am pretty sure the Fluke gets the current wrong for DCC as when I measure stall currents with DC and do the same with DCC (on a separate piece of track) the value is lower, so I am wondering if the RRamp has a different algorithm.

I suspect it is not your Elite, I don't know which decoder you are using but if you are using a Hornby one for a Ringfield motor powered loco then probably you have damaged it. Ringfield motors are on the current limit for a Hornby decoder and quite a number of others as well. So sometimes they work ok but then if the motor draws slightly more then they seem to fail. Hattons do the same. I have a second hand Elite I got off EBay. I must admit other than the rotary control settings it is incredibly reliable. If you have a 5 pole Ringfield motor they seem to draw less current, but the early 3 pole ones can draw up to 0.8 amp. I use Zimo decoders which are a little bit more expensive at £20.00 compared with about £16.00 but they are rated at about 0.8 amps and so far have no issues driving older locos.

I assume if is anything like the software I worked on, you can probably get the update to work on a Windows emulation running on a MAC, it is when it tries to write the data to the communications port. To write to the USB port it probably uses a Windows .dll file that links the software to the operating system and computer hardware, they don't work too well on a windows emulation. I thought I did read on here someone did get it to work, but I might be wrong

I know my original dummy car dragged a lot. I found a lot of it was due to the pickups that are used on that model, also the wheels don't run in any sort of bearings. In the end I uprated the dummy car to the latest Railroad Spec one.

If the chip had burnt out then you cannot read CVs, but seeing as you have a short I doubt you can anyway. Normally though if the decoder if working you can read CVs.

It sounds like your decoder has failed, did you smell any burning? What you need to do is take out the decoder replace it with a DC header and check that the loco works on DC. As to the purple wire that is an extra function which you wire something to. The reason it is left as a flying lead is there are not enough pins on the connector to connect it. The important bit is that its end must be insulated to prevent it touching anything and damaging the whole decoder. I normally either sleeve it or paint over it with clear nail varnish. Yours appears to have some copper showing which is not good.

I decided to fit sound to my new Hornby Thompson A2. Anyway as Hornby don't do a suitable TTS decoder and nobody seems to know what it sounded like, I decided to use a A1/A3 TTS decoder. Anyway normally I use Iphone speakers but for once I decided to use the round one included with the kit. When I came to fit the speaker in the mounting supplied I suddenly found that it wouldn't fit that well as Production had routed all the wires through it. Looking around I found underneath the DCC socket mounting there is an oval hole in the weight which was obviously meant to pass all the wires through. So in Production I suspect the idea was to wire everything up pass the wired DCC socket through the oval hole in the weight and then screw it down.Trouble is somebody redesigned the DCC socket PCB, which is a bit wider so it no longer passes through the slot. So they resorted to the old way of passing through the speaker hole. So in my case I had to do a rewire to get the speaker to fit properly. I just thought it was funny that they went to all that effort and still messed it up.

Yes, exactly. No, I am not sure but it looks logically correct. I don't have any two pin bi colour leds or else I would try it out.

I think you can do it. From the blue wire take two 1 kilo ohm resistors connect the other end of each resistor to each lead of the led. Now connect the white wire to the junction of one of the led leads and the resistor and the yellow wire to the junction of the other led lead and the resistor. I think that should work.

Ok, I know it is not Hornby but I know a lot of members have these. A friend asked me to look at his loco because everytime he put it on the tracks the controller tripped out with a short circuit. The loco has a Loksound decoder in it with the sound option. After taking the loco apart and using my decoder tester I found that the decoder had gone short circuit, in fact I narrowed it down to two of the bridge rectifier diodes going short circuit. Now obviously it is dead, but the thing that surprised me, on any other decoder that goes short circuit there is a burning smell and the diodes fry. Definitely with TTS decoders that is what happens. With this decoder there is no obvious damage. The friend said it just stop working and put a short across the track. It was in a Bachmann Jubilee tender, so no concerns with cooling. So my question is, is this a common failure mode with these? I have since replaced it with a Zimo 21 pin decoder and it is working happily, so no wiring issues on the loco. So why did it die?

I think the decoder is still listed in their 2021 catalogue, so I suspect that it should be available sometime this year. It happened with their class 47 decoder last year. You can buy a Zimo sound decoder or loksound one that will do the same, although the cost is about £100 compared to the £36 to £40 for a TTS decoder. I must admit though the more expensive ones do sound much better.

Thanks 96RAF, the dual packs are not due in until June/August, but the Merchant Navy one was really good value.;

My two favourites are the 8 pin DCC connector or the capacitor across the motor. On some of my Hornby locos I have found that the 8 pin socket that holds the DCC decoder doesn't always grip the pins properly, so basically as your loco goes over a bump you get a loose connection. The other issue I had with my class 66 was the suppression capacitor across the motor. In my case it went short circuit and took out the TTS decoder, but sometimes just before they die capacitors do funny things, so it could be occasionally be putting a short across the DCC motor output.

Has anyone got any idea if any of the current TTS decoders are suitable for the new Hornby Thompson A2 locos? I know they are derived from the P2, but I assume during the Thompson rebuild the boiler etc changed so I assume the P2 sound is not relevant anymore..

If you want to change the lights, I found the kit that someone does on EBay was really good. Initially I used red and white tower leds, which meant running wires between the chassis and body. The EBay kit was a small PCB with white and red lights that fitted on the chassis, meaning that the wiring could all be on the chassis. So when you lift the body off, the lights stay on the chassis. Here is the link: https://www.ebay.co.uk/itm/Hornby-HST-LED-Lighting-Upgrade-Kit-New-Version-Updated-Design/251999154032ssPageName=STRK%3AMEBIDX%3AIT&var=554330132611&_trksid=p2060353.m2749.l2649 Moderator message - above link doesn't work when copied and pasted - here is a tested working version of the link above - also made clickable. Hornby HST LED Lighting Upgrade Kit, New Version, Updated Design.

I think the way I did it TE, was to buy a A1 tender base from a non Railroad model and rob the pickups from it. The thing I found was if you buy the tender base for the non Railroad version the tender top won't fit. So what I did was buy the A1/A3 tender bottom that had pickups on it and remove them. I think if I remember on these they are attached by bent tags, so carefully unattach them. Now attach them to the original tender by making a small slot for each in your original tender. I also bought the 4 pin lead and socket and mounted the socket in the old tender. I then modified the wiring. What you need to do is what I did, search Peters spares for A1 tender bottoms, fortunately he has a reasonable amount and pick one that has pickups and is similar in shape to yours. Once you know which one you want, do a search on Lendons website, sometimes theirs are substantially cheaper and if you are only buying it for the pickups, the cheaper the better. I hope that helps.

As I said in my earlier post, the Hornby TTS decoder works with this model. That will provide sound and DCC function. At the moment Hornby are out of stock, but eventually they will get stock as it is in their current catalogue.

No problem with buying from China most of my components come from there. Most of them are made there currently. The issue you get with the Chinese is they advertise lamps as Leds, generally I imagine because very few people want lamps anymore. I found out to my dismay when I ordered some Led station lamps, only to find that they were bulbs. Right now the technical stuff, leds have a forward voltage drop of 2.2 volts and they only conduct current in one direction, so if you put a voltage across them one way they will light, the other way they will not. Lamps don't care what way round you pass the current. So to make a led light up you need to put a resistor on one of the leads that connect to your power supply. Normally the current has to be in the region of 5 to 20 milliamps, so you use ohms law to calculate it. Alternatively, use a 1 kilo ohm resistor, that should at least stop the led from blowing up. If they are bulbs you just put 3 volts directly across them. I hope that helps.