ColinB

Probably not, Sam was complaining about another wagon that had plastic wheels.

I suppose this is me moaning but I thought I would share the experience with others just in case they fall into the same hole. I bought a Duchess loco off EBay with no tender. No issue, I have enough bits to make a tender although I am still looking for the proper tender top (black one that fits the black City of Leicester). Anyway convert it to modern spec so the decoder is in the tender and then try to run it. It seemed to derail at the same point on my layout. Adjust the back to back spacing and still it derails. Then I found it, someone had removed the flangeless pony truck wheels and replaced them with the flanged type. This is the second loco that has had this issue. Of course Hornby don't have a part number for this part so buying a replacement is out of the question. Fortunately they do a Princess one so I assume that is roughly the same. The thing that surprises me is it only derailed on one curve. I assume its previous owner only had straight track.

This is standard old Lima design, the power bogie frame clips over the driving wheels to hold them to the power unit, it clips on, so you can unclip it. if you look down behind each wheel you will see the clips. You have to be ever so careful as they will snap quite easily. You might be able to fit them in situ using very thin long nose pliers. Alternatively take off the body by unscrewing the 2 body screws (I don't know if the modern Railroad has them but there are holes for them in the chassis) then unclip the body. You will then be able to unclip the power bogie from the chassis. I recently rebuilt some Lima HSTs to fit the new Railroad chassis so I know a lot about how they go together.

I did a search for the post but I could spend all day looking. I took my one apart. It appears I used a rewired Zimo module but I suspect a Hornby one would fit.

I can't remember which one I used but I do remember posting on this site which one. I used to use Zimo 6 pin ones and rewire them to 8 pin but Zimo decoders are now super expensive and hard to obtain. The Train o Matic ones are very small and they use the same decoder for 8 and 6, so they have done the rewiring for you. I can't remember whether a Hornby one fits. I suppose the easy solution is to take my one apart again or find my post.

I think it just clips on, I am sure there was a post about this but I cannot find it.

Is the SUSI clock and data equivalent to the TB clock and data on a 21 pin socket?

SteveM6 you are so very right. Some of the responses on this thread are so misleading. From what I read the loco has gone back to Hornby, once they realise it is not the first motor they have changed in this loco, they will probably dig a bit deeper or give the guy a new one.

Trouble is with modern multimeters you do not know what you are measuring, the thing could be reading peaks which would explain the higher voltage when it is running. In the old days an avo was best for this sort of thing or in my case a decent Fluke multimeter. As someone said, with a load the voltage will fall.

All I can do is advise, I have been down this route many times on this site, so I am not going to argue. I doubt it is a "mains" transient because sitting in between is a piece of relatively sophisticated electronics namely his controller. Long gone are the days of just a transformer and bridge rectifier, so generally the controller electronics would go first. I doubt he lives next door to an industrial arc welder that can generate those sort of transients. I would be interested to know though when the fault gets fixed.

Well Silver Fox 17 I am not a Hornby Engineer so I don't know what the design fault it is. What I do know is that when you make a product it is meant to withstand normal use. Now from all I have read all the guy has done is put it on the track and run the loco. It may be his controller gives out 24 volts that would definitely kill them but then he would notice that as they would run considerably faster. I suppose if it was PWM then it might happen but you still have to get enough energy into motor coils to burn them out. The favorite is the gearing gets stuck and before the user notices the motor has burnt out. As I said before we know how quickly these motors can burn out and I have seen a dcc decoder fry on a point where the loco got jammed because the back to back spacing was wrong. It could be the motors, as I said I found that Railroad Pendolino motors were extremely bad, one in three failures is not good. The only person that will find out is Hornby, if they have to replace enough motors, they will look a little deeper into their product and find out how it can fail.

Virtually everything in life follows the bathtub curve, unfortunately even the life of a human being. Either way, I would really like to know what is killing the shunter motor. I suppose the thing is, it is obviously a design fault, as unless the user is doing something silly it should not be possible to break it easily. I imagine that the user doesn't really want to send back again because I know I would get embarrassed doing it, but it sounds like that is what they are going to have to do. It flags up to Hornby that there is an issue with these models, as nothing I have read in the posts says that they are abusing the loco.

Yes SMR248 you are right about the stalled motors, I watched Sam of Sam's Trains demonstrate how to burn out a Hornby 0-6-0 motor, even he was surprised how quickly it melted. As to Hornby and quality, there is no secret there there are loads of posts about the lack of QA on their models that is why Sam has a field day, it is very difficult to do remote QA. The Chinese think 10% failure rate is good. Years ago when I first started in Engineering you would test a part for ages to see how long it lasted, very few people do that anymore. All of this brings it back to something must be getting stuck in the loco, causing the motor to fail.

No SMR248 you can't, you are into Flemming's laws if I remember rightly. As I said before the only time you can use it, is for the stall current. Either way, none it it matters in this instance, you put the loco on the track and it draws what current it needs. I am at a loss to figure out what is blowing them up, track layout definitely shouldn't, perhaps a better solution is to ask Hornby.

Yes you right Daedalus but you can use Ohms law to get a rough indication of the stall current, I am sure years ago it was one of my lab experiments on a very large dc motor. Some of the electrical descriptions I have read on these two threads I find amazing. The thing that does intrigue me though is how are they getting blown up, the only way I know to blow them up is to stall them or put too much voltage on them. AC seems to be able to kill them but generally the loco doesn't work, it just buzzes. Hornby don't use coreless motors as far as I know, so it is not that. Unless of course there is just a bad batch, they are Chinese and from Hornby, both of which have dreadful Quality Assurance.

It was a good reminder to add "stay alive" to all my 0-6-0 locos, now I have found it can work properly.

A point will not blow up a motor. The loco might stall on that point because the back to back spacing is wrong on the loco. The motor then draws maximum current and burns out. I burned out a lot of DCC decoders that way. The motor will only draw its maximum stall current so whether the short circuit protection is 5 amps or 20 amps it makes no difference. Now possibly if the motor stalls and the armature overheats causing the insulation on the armature windings to melt and fuse the wires together creating a short. The 5 amp limit will have an effect in that there will be enough power to melt the motor but by that time the motor is damaged beyond repair anyway.

I agree with you Fishmanoz entirely, none of it would have an effect on the motors, which is what I have been trying to say.

The solution I have found is installing a decent "stay alive". I found some "stay alives" you couldn't read back values in programming mode but I found if you buy a more expensive one, then this is not an issue. The issue I found even with electrofrog points, most points are a bit uneven so the 0-6-0 doesn't always pickup power properly. The bigger issue is finding room to fit it all.

Reading all the posts he said there was signs of melting around the motor, two things can cause that either his controller is sourcing an extremely high voltage or something is getting stuck on the gearing. Now if there is something wrong with the motor then you could get arcing that could possibly do it. I don't think his layout could do it with shorting clips or not, electricity doesn't work that way, if you get a short the motor doesn't work. He says Hornby have fixed his locos so they would have checked the motors, so probably the fault will go away.

I don't know if this is any help but I replace a lot of my Railroad 3 pole motors with Pendolino 5 pole ones. On a lot of the motors I get I have noticed the clip that holds the magnets in is not attached properly when they were made, so they run alright for a little bit until the magnets drop onto the armature and jam. I generally fix them and I can usually tell when I spin them. I get roughly one in three that have this issue so it could be the motors. Although electronics is very sensitive to surges in power, generally motors smooth them out , it would have to an extremely big surge to blow up a motor, remember we are talking about a 20 to 1 reduction ratio. Was there any burning smell coming from the motor? Even if the power supply was giving too high a voltage you would notice, by the loco running faster.

I use LaisDCC decoders if I need a lighting function on a loco. These are the cheapest DCC decoders you can buy and are ideal for lighting functions. Also it is a good idea to invest in a DCC decoder tester, it makes it a lot easier to figure out if the decoder is working properly. Again LaisDCC make a really cheap one.

I finally got to it by doing a Google and selecting a sub index.

Anyone tried accessing the YouChoos website in the last day or so. It appears not to work, any idea what is the issue?

I know the feeling, that is why I replaced or converted all my tender driven locos to loco driven. As someone said make sure everything is lubricated, I also had issues with the cylinder block where it had cracked and was not properly aligned with the valve gear.