ColinB

I don't know, it is the size that is most important, I suspect any N gauge one should do. I found this one https://www.coastaldcc.co.uk/products/lenz/decoders/n-gauge/ it is a bit expensive but it looks small.

Yes, you are exactly right they are out of stock everywhere. Hopefully they should soon be in stock again. Trouble is I get the opinion nobody has made anything since March.

In the places where there was a supporting beam under the points and I needed to use surface mounted point motors, I used Seep GMC-PM20D surface mounted ones. I was really surprised, they work really well.

I must admit with all the decoders it is really difficult interpreting the specifications. A lot of them are incredibly optimistic, I suspect they are quoted for testing the decoder in "open air" where it has adequate cooling. I have converted a lot of my old Bachmann and Hornby locos so I did the stall test. I then selected the right decoder decoder according to the requirements and then managed to destroy them with "overcurrent". When I mailed one manufacturer they said it must be an overcurrent issue, since then I no longer use their products. Sadly, although I don't like doing it, I stick to the German and Austrian products as their specifications seem to be correct and if I want to know more I just mail their Supplier and I get a true valid answer, the others even if I get an answer it is usually from a sales person rather than real technical support. I tend to use only one supplier for decoders, if you read my posts you will gather which one it is, they are they only ones that have only failed when I have done something stupid. The only deviation on this policy is TTS decoders, but you have to be so careful with these.

@Chrissaf the LaisDCC board I am talking about is the 21 pin breakout board. I normally use the LaisDCC breakout board, but I have just finished doing one with the Strath adapter. I prefer the LaisDCC, although it is harder to wire as you have to know the corresponding 21 pin equivalent. It has plated through holes on the PCB and is easier to solder to. In both cases, yes you have to cut off the 8 pin connector, but in my case I test it on the tester before I cut the 8 pin header off. If by chance it fails, then I have to resolder the 8 pin header back on, but they is just a price you have to pay. I must admit it is a much neater arrangement and tons easier to insulate.

The Strathpeffer Junction one is easier to wire up than the LaisDCC one, although the LaisDCC circuit board is better made, although the LaisDCC one means you need to know which pin on the 21 pin socket does what. With the Bachmann class 70, look in the data that came with the loco and look for the light functions. Usually Bachmann only use 3 functions front lights, rear lights and cab lights., on the ones I have converted (class 37, class 47 and class 66). Dapol tend to use all 6, as do Hattons on their class 66. I always use the breakout board, the converters to me once fitted are too high and unless you are lucky, make it difficult to put the body back on. I did actually damage one TTS decoder using a converter, but as I said before that was on a class 37, where there is not much space between the location and the roof.

Yes, you can. I have done it with many of my Bachmann diesels. The only issue I have had is the 21 pin to 8 pin adaptor is too high in some locos, so you can't get the body on properly, which is a particular issue with class 37s where there are light connectors at the bottom of the body that don't make contact. You are better off getting a 21 pin "break out" board LaisDCC sell them so does another firm. You then rewire the TTS decoder to the breakout board. You can also wire the speaker wires which allows you to wire the speaker to the main PCB of the diesel. If I remember rightly in Class 66s you can use the adaptor there is enough height. The only thing you have to be aware of is some locos use all 6 functions for lights, so if if you use an 8 pin TTS decoder you may lose some functionality eg. Hattons class 66 and some Dapol diesels.

Why don't you do what we used to do with analogue systems have separate lengths of track separated by nylon fishplates then enable each section with a switch connected to the DCC supply. That is how my system is wired up. Then if you think you have a short on that section just turn it off. I cannot see why you cannot use circuit breakers on DCC if they trip at the right value, the only issue you will probably have, is that the controller will probably trip before the circuit breakers do. Switches is the easiest.

I am not sure that is their logic, they released the last class 47 without releasing a new loco. I think it just comes down to whatever sells. Class 37 and class 47s will always sell, they are the two locos that seem to fetch a premium on EBay. They seem to always have stocks of A4s and A1/A3s.

It is the same one that is in the 0-4-0 and it is clipped into a sprung steel cage.

No howbiman that is the later type, but thanks for looking. I eventually answered my own question, I have a couple of old 0-4-0 chassis with can motors in. It appears they used one of those in this model, because I swapped the old one out for the one in the 0-4-0. I did find out one thing though, I now know why Hornby don't put decoder sockets in their 0-4-0 locos. These motors have a stall current of about 0.8 amps according to my Fluke, so if you fitted a standard Hornby decoder it would die. I only noticed because a DCC concepts decoder could not turn the motor, so I started checking the current. The DCC concepts decoder current limit, but it leave them too long doing it they die.

I have a really old GWR 0-6-0 pannier tank engine. I took it apart to find a Scalextric type motor. It is not the later Thomas the Tank, neither is it an X03/X04 type motor. It looks like it must be a version between fitting the X03/X04 motor and the late very thin motor. It drives the centre wheel. I have tried finding a Service sheet for it, it looks like 84B covers it, but I cannot find a part number for the motor and on this sheet it looks like they refer to an X03/X04 type motor. It is the part number for the motor I am really interested in, as my one in this loco is drawing a lot of current and I am hoping I can replace it with a better one.

I assume you have the DCC decoder in the right way round. The easiest and most secure way to get the motor working in the right direction is to reverse the wires on the motor. If you do it using CV values if you ever reset the decoder you will have to do it again. The bigger question to me is if it is a standard class 66 why is the motor wired up wrong. I convert a lot of my old locos to DCC so quite often they go the wrong way, but it never bothers me, I just turn the controller in the opposite direction. As to the othe CVs I haven't got a clue. I have a Hornby Evening Star with a TTS decoder and other than the documented issues with motor capacitors, I find it works perfectly ok. Do a double check on whether the decoder is in correctly, on this loco it doesn't have lights so you would never really notice if it was in wrong.

I suspect they mean the steam one. For the class 66 one there is already a suitable TTS decoder. I have that the class 66 Evening Star from Hornby but when anyone mentions Evening Star, I always think of the steam one.

It might just need remagnetising. The red glow is where it is drawing too much current. I would stop running it before you burn out the motor. You could try buying a new neo magnet, I found they work for this type of motor.

What make of decoder are you using, I assume it is not Hornby as they cannot handle the current? Have you removed any capacitors around the motor?

I agree with Going Spare, I had enormous issues with a couple of my Duchesses, the wheels in my case rotated, but once on the track they just slid along. Eventually I traced it to the valve gear and cylinder block. If it does not line up nicely, then that is what happens.

Thanks Fishmanoz, hopefully all the dodgy ones have gone. It is the one item, that I only buy from a recognised retailer, just in case you have to send them back to Hornby. A couple I have damaged by me doing something wrong which I will own up to, but I have also had about 3 that have just failed, or lost sound or the sound was distorted. Another one kept losing sound, but works perfectly in another loco.The one in the HST just died while it was running around the layout, it was a hot day and it was driving a 5 pole ringfield motor, but it had worked perfectly for 6 months. Trouble is deugging software faults costs a lot of time, effort and money, so I suppose some of the very rare issues never get resolved. The only thing that worries me is I have a lot of locos, with quite a lot fitted with TTS decoders, I am always worried that one will just die when I run it and it will probably be out of warranty.

Yes, in automotive a tuner/calibrater sets the values. In theory Hornby should set them for every model they make sound for, because only they know the characteristics of their motor. It is all to do with overdamped and under damped systems. If it is underdamped it oscillates which is why you get the juddering. I must admit setting cv150 to 1 seems to cure it on all my diesels, I was trying to think if I had to set it to 1 on my class 66, which is the only Hornby diesel I own with TTS. I would imagine with a steam loco, the valve gear acts as a damper, hence why it is not such an issue plus originally when it was setup that is probably what Hornby used to set the values. P is probably the amount of proportional feedback you use from the back emf, I assume there must be a cv for I and likewise D, but generally you can spend hours trying to get it perfect. I am just happy to set cv150 to 1.

I didn't see this post until now. If you are going to buy a Hornby class 37 loco, then to me the most important thing is the pickups. The issue with ringfield motors is that they pick up power only on one side of the bogie, so the front bogie will pick up power from the non geared side and the non driven bogie from the other side. If you can put an extra pickup on the trailing bogie to pick up power from both tracks it makes running so much easier, because of the traction tyres on the driven bogie you don't gain much by having pickups on both sides. The late non ringfield motors already have this, so they run better. I must admit I use Bachmann class 37 locos, they are so much better, but unfortunately so much more expensive.

PID is Proportional Integral Derivative is the control loop for controlling a motor ( I had forgotten all this stuff), I assume in this case they are using the requested speed and the back emf as the parameters. i assume back emf is the feedback parameter. If you are into cars, it is used to control the idle speed control. I wrote a ton of software to do exactly that. That explains why it judders.

@Jimyjames I have no issue with your posts, you are always constructive and friendly, so no problem. That is exactly what the forum is for.

That is really weird, turning the chip round shouldn't make any difference. It is not my old friend the "dodgy" socket. I have found on some TTS decoders the pins are thinner than their normal decoder counterparts, so you get a lot of loose connections. I had one where the sound didn't work properly, but normally they go backwards and forwards ok. I have also had issues where they lose sound on one loco, I later traced that to some interaction with the motor, it works perfectly ok in another loco.

If you are going to pay £90.00 for a class 60 one on EBay you might as well buy a Zimo one, they are only £99.00. TTS decoders are good value as long as they are less than £50.00, above that you might as well consider one of the expensive ones. At the moment Hornby are working from home so you can't really blame them for running out of stock, it is just like trying to get Peco points. Even people like YouChoos have run out of certain types of Zimo decoders, so for once I don't think it is Hornby's fault. I suspect Hornby don't make these, I think they just probably give the supplier a file suitably formatted for them to load, so the thing is with Electronics there is normally a minimum number for a production run and it is usually in the thousands. I remember the difficulty I had once trying to get 10 off of a SMD populated PCB. It it had been thousands no problem, but ten, not worth setting up the machinery.

I don't know, perhaps I have got mixed up with class 56. I will go look at the Service Sheet but normally they are not that detailed, but thank you for the information. Quite often you see ones secondhand that have issues with the lights which is what made me wonder. I have just looked at the Service Sheet and basically it shows a PCB with wires attached, but no mention of connectors, so it isn't much use. I suppose I could google the spare parts listed that might help. It looks like I have answered the question, there are some photos on the web of the chassis after I searched the only PCB part number listed. It looks like it uses normal connectors, so hopefully not an issue. Thank you RAF96 I would never of thought of googling the PCB part number, if you hadn't pointed me towards the Service Sheet.