Metadyneman wrote:I can confirm what Bigmet and SRman have said about the cause of this problem and I can put a few more bits of meat on the bone to clarify what it is.
....It all boiled down to the yellow disc like item on the PCB which looks like a capacitor but is in fact a re settable fuse otherwise known as a "polyswitch". A polyswitch is set to break an electrical circuit when it reaches a certain temperature and it re sets itself when the temperature returns to normal. It is clear from the rating on this "polyswitch" that it is not up to the job and it's cutting out the motor far too soon . The loco will grind to a halt after about 10 minutes with a load whether it is on DCC or DC. (I know this because I replicated the fault using DC and DCC). We experimented with various things including removing the polyswitch (because it was initially thought that it was a capacitor). We eventually worked out that by bridging the polyswitch with wire, the loco would run happily for more than an hour without showing any signs of stalling, slowing down or stopping.
I have been in communication with Kernow Models regarding this and they have said that they cannot comment yet until it has been established whether or not bridging the polyswitch invalidates the guarantee or if indeed the component is in fact faulty. I think it is just a matter of time before we hear something but for now, my D600 is perfectly happy running round without a polyswitch in the workings!!
It is interesting that you found that the loco grinds to a halt after 10 minutes. Mine does it after travelling 2-3 metres on my workbench test-plank! Video below to prove it.
In order to demonstrate the problems I am having with the loco, I have created some YouTube videos. It should be noted that all of these videos were done within the space of a few minutes and the loco had been idle for about a week, so had no prior 'running in' to the videos being done. What you will see is a record of the entire 'operating session'.
Video 1 (MVI_0257.MP4) See: https://youtu.be/V-HcUTofEog
This shows the loco running up and down on my workbench test 'layout' which is about 3M long. The loco is fitted with a brand new Loksound 4 (which has been successfully tested in another loco), although in these videos, the sound isn't being used. I have set the motor control CV's to be the best I can get (slightly adjusted from those published by SWD). Control is with a Lenz 100 DCC system, although exactly the same results occur with my NCE system on my layout.
The loco is being started slowly with a slow acceleration. At the 15sec mark, you'll notice that it 'lurches' forward. When I slow it down, you'll notice it jerking and leaping forward at the right of the picture. I then bring it back from right to left, then left to right and at the end of the video, you'll see some significant jerks/leaps forward.
No matter what motor CV setting combination I use, I just cannot stop the random jerking and leaping.
Video 2 (MVI_0258.MP4) See: https://youtu.be/Y2DIqxCuYo4
This shows the loco being run at a higher speed. When it reaches the right of the picture, it lurches badly when stopping. I then start it from right to left (my commentary mentions the jerk) and then when it gets to the left, it dies completely. Remember that the time you have been watching these videos is the length of time I ran the loco, so while some people have had the loco die after 10-15 minutes under load, I have shown you that mine dies completely within a minute having being run no more than a couple of metres!
Video 3 (MVI_0261.MP4) See: https://youtu.be/frNXEz0NEKo
This shows the effect of bridging the orange 'ceramic capacitor' under the decoder which Kernow recommended I did.
The modification severely affects the speed such that it is no more than a crawl. People on RMWeb are reporting that the 'orange ceramic' is a cut-out fuse. If that is the case, then it would be wired in series and shorting it as I did should not cause a dead-crawl maximum speed, rather, speed as before but without going dead. The fact that dead-crawl speed resulted suggests that it is a suppression capacitor wired across the motor and that shorting it as I did effectively shorted the motor. But similarly, if this was the case, the loco would not have moved at all. Something very strange going on here...
In order to test these theories, I later cut one of the leads to the 'ceramic' to create an open circuit. If it was wired in parallel across the motor as most other manufacturers do for suppression, then doing this should have had no effect and the loco should continue to run. The loco was totally dead, suggesting to me that this 'ceramic' is wired in series and is not therefore, a suppression device. I believe that the RMWeb commentators are correct that this is indeed, a cut-out fuse.
Video 4 (MVI_0262.MP4) See: https://youtu.be/z9xn-j1EU6o
This video shows the loco, having removed the bridge. Speed returns to normal, but there is random jerking and the loco even 'launches off' before it stops. Clearly, the decoder is totally and utterly confused by the electronics and/or motor in this loco.
I actually like the loco - it looks great, but I just cannot to get it to work on DCC at all. I have never had problems like this with any locos in the 20 years I have been using DCC. It runs perfectly on DC though! Maybe it is designed for DC users and not for DCC. I have also put a Lokpilot non-sound decoder in it and got the same results. In may case, this loco will not run with ESU decoders properly. Some well known sound providers have told me that they have had the same problems with the Loksound 5.
How can a loco get to market which doesn't even work with a top-of-the-line decoder ?
I am of the view that the motor/electronics this loco has is just garbage and I am half tempted to rip them out and fit a conventional motor.
Sometimes, I wish people would not experiment with untried technology! I have never had problems with Portescap motors in the brass kits I have built - ESU's worked out of the box with them, so there is something very strange going on with this loco.
One only has to look at numerous YouTube videos to see jerky behaviour. For those people who use Scalextric controllers as throttles, they probably wouldn't notice the issue, but for those of us who prefer something a little more refined, it is very much a problem because the loco cannot be run smoothly at low speeds without random jerking.