Kernow D600 Warship

Ask questions or give advice on any other model railway Manufacturers and Gauges
User avatar
SRman
Posts: 1148
Joined: Fri Oct 03, 2008 2:26 am

Re: Kernow D600 Warship

Postby SRman » Thu May 09, 2019 11:45 pm

As Bigmet has said, it isn't anything to do with DCC, but it is a component that is at fault. There is a similar topic on another forum (starting with "RM" and ending in "web") and their fingers are pointing at a resettable fuse on the PCB. It looks like a capacitor but is an in-line fuse. The component sits under where the decoder plugs in, according to those who have been trouble-shooting their models.

Bigmet
Posts: 9120
Joined: Tue Aug 14, 2007 2:19 pm

Re: Kernow D600 Warship

Postby Bigmet » Fri May 10, 2019 10:37 am

Further to which, that there is a difference between the first group of releases - no such trouble reported - and the second group where this 'cutting out under sustained load' problem is observed, is helpful. (That's experience from owners of both who can make the comparison.) Hopefully that will give Kernow a lead in looking for the difference between the two groups of models.

User avatar
Metadyneman
Posts: 1171
Joined: Wed Apr 11, 2007 9:09 am
Location: Portslade-by-Sea East Sussex

Re: Kernow D600 Warship

Postby Metadyneman » Sun May 12, 2019 8:50 pm

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 was I and another two contributors to the "other forum" who actually discovered exactly what the problem was. We spent one afternoon afternoon discussing it and testing various theories on our layouts.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!!
A bargain is something you really don't need at a price that's completely irresistible!!

Bigmet
Posts: 9120
Joined: Tue Aug 14, 2007 2:19 pm

Re: Kernow D600 Warship

Postby Bigmet » Tue May 28, 2019 12:06 pm

Om the positive front, I see that at least one owner has been saved from burning out his coreless motored D600, thanks to the 'polyswitch' fuse action, when he plonked his newly received model without decoder onto a DCC track, intending to test run it on 'address 0'. Without the overcurrent protection, the minimal heatsinking of a coreless motor will lead to rapid burnout if the DCC track current is given 'unrestricted access'. ALWAYS with a decoder interposed in the circuit for operation on DCC...

User avatar
SRman
Posts: 1148
Joined: Fri Oct 03, 2008 2:26 am

Re: Kernow D600 Warship

Postby SRman » Tue May 28, 2019 11:32 pm

If anyone is interested, my D602 arrived two days ago, and after running in on DC I fitted a decoder. I had a choice of Dapol Imperium or Zimo MX638D. To make it easier to match and work with my recent class 22 purchase, I chose the Zimo decoder.

On testing, it ran beautifully but some of the lighting functions didn't work (all were OK on DC). Now, there is a useful little trick with Zimo Mx634 and MX638 family decoders: you can change them from having logic outputs to powered outputs on the auxiliary functions, and back again. Putting a value of 3 into CV8 changes the MX638D to an MX638C (ditto for the MX634). Doing this gave me all lighting functions - F0 = directional marker light/tail lights, F1 and F2 work the cab lights at each end, and F3 and F4 work the headcode lights at each end.

If you need to restore your Zimo decoder to the 'D' variant, program CV8 with a value of 4. Doing this does not actually change CV8, which is a fixed value showing the manufacturer's unique identifier code - there is some sort of magic electrical trickery involved within the decoder that simply works!

gppsoftware
Posts: 306
Joined: Thu Mar 09, 2006 5:34 am

Re: Kernow D600 Warship

Postby gppsoftware » Mon Jul 01, 2019 12:34 pm

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.

Graham Plowman

Bigmet
Posts: 9120
Joined: Tue Aug 14, 2007 2:19 pm

Re: Kernow D600 Warship

Postby Bigmet » Mon Jul 01, 2019 2:50 pm

Graham,

Sympathetic to the fact that you are half the world away from the retailer, in your shoes I would be inclined to think that the 'polyswitch' on your model is an oversensitive example. The easiest courses of action seem to me: to take it out of circuit and rely on your own common sense to prevent an overcurrent condition on the motor; or source and substitute a new 'polyswitch' component* if you wish to retain the protection. Simpler than going for the general rebuild job, and still leaves that option available.

*Would Kernow send a spare if asked I wonder? They are a good outfit by general report, and must now be aware that this problem is real. (Bear in mind I have never dealt with them, since they don't produce anything I need, but do know a couple of satisfied customers.)

Very much at your own risk of course, but you have the experience behind you to do this stuff...

gppsoftware
Posts: 306
Joined: Thu Mar 09, 2006 5:34 am

Re: Kernow D600 Warship

Postby gppsoftware » Tue Jul 02, 2019 12:27 pm

Bigmet wrote:Graham,

Sympathetic to the fact that you are half the world away from the retailer, in your shoes I would be inclined to think that the 'polyswitch' on your model is an oversensitive example. The easiest courses of action seem to me: to take it out of circuit and rely on your own common sense to prevent an overcurrent condition on the motor; or source and substitute a new 'polyswitch' component* if you wish to retain the protection. Simpler than going for the general rebuild job, and still leaves that option available.

*Would Kernow send a spare if asked I wonder? They are a good outfit by general report, and must now be aware that this problem is real. (Bear in mind I have never dealt with them, since they don't produce anything I need, but do know a couple of satisfied customers.)

Very much at your own risk of course, but you have the experience behind you to do this stuff...


Thanks Bigment, I originally hail from Sussex, so I know Kernow and have no complaints about their reputability and will certainly continue to purcahse from them.

Per suggestion, I will take the poly switch out completely and replace with wire.

User avatar
Metadyneman
Posts: 1171
Joined: Wed Apr 11, 2007 9:09 am
Location: Portslade-by-Sea East Sussex

Re: Kernow D600 Warship

Postby Metadyneman » Fri Jul 05, 2019 10:31 am

gppsoftware wrote:
Bigmet wrote:Graham,

Sympathetic to the fact that you are half the world away from the retailer, in your shoes I would be inclined to think that the 'polyswitch' on your model is an oversensitive example. The easiest courses of action seem to me: to take it out of circuit and rely on your own common sense to prevent an overcurrent condition on the motor; or source and substitute a new 'polyswitch' component* if you wish to retain the protection. Simpler than going for the general rebuild job, and still leaves that option available.

*Would Kernow send a spare if asked I wonder? They are a good outfit by general report, and must now be aware that this problem is real. (Bear in mind I have never dealt with them, since they don't produce anything I need, but do know a couple of satisfied customers.)

Very much at your own risk of course, but you have the experience behind you to do this stuff...


Thanks Bigment, I originally hail from Sussex, so I know Kernow and have no complaints about their reputability and will certainly continue to purcahse from them.

Per suggestion, I will take the poly switch out completely and replace with wire.


I note you say you have tried many different CV settings to eliminate the jerking. My model did the same thing as yours in relation to jerking until I adjusted CVs 54 & 55 to the value of 10 which are the recommended settings that Kernow advise for a Loksound 4. Mine is fitted with a Bachmann 36-557 decoder (essentially an ESU Lokpilot) and those settings work with that as well. Not suggesting that you haven't already tried it but if you haven't, that may work. As for bridging the polyswitch, I would suggest total removal of the polyswitch and bridging the two points where it was soldered to the pcb with a short piece of wire.
A bargain is something you really don't need at a price that's completely irresistible!!

gppsoftware
Posts: 306
Joined: Thu Mar 09, 2006 5:34 am

Re: Kernow D600 Warship

Postby gppsoftware » Fri Jul 05, 2019 1:55 pm

I note you say you have tried many different CV settings to eliminate the jerking. My model did the same thing as yours in relation to jerking until I adjusted CVs 54 & 55 to the value of 10 which are the recommended settings that Kernow advise for a Loksound 4. Mine is fitted with a Bachmann 36-557 decoder (essentially an ESU Lokpilot) and those settings work with that as well. Not suggesting that you haven't already tried it but if you haven't, that may work. As for bridging the polyswitch, I would suggest total removal of the polyswitch and bridging the two points where it was soldered to the pcb with a short piece of wire.


I have indeed tried 54 and 55 set to 10 - thanks for the suggestion - these are the recommendations put out by SWD to Kernow. These were my first efforts at resolution a few weeks ago. I actually found higher values gave 'better' results.

I have now removed the polyswitch and replaced it with a strip of wire on the motherboard. Same as my video where I bridged it, the loco barely has enough power to move itself, but if you push it, the wheels do revolve. In the opposite direction, they do not turn at all.

This evening, I have disconnected the track pickup wires from the motherboard and the motor connections and have wired them into a temporary 8 pin socket so that I could fit one of my 8 pin plug Lokpilots and bypass the motherboard. This is effectively wiring the motor directly to the decoder.
Same results as before with no motion. The motherboard is not the issue.

Looking at the motherboard, the polyswitch is wired in series with the pickups ie between the track and the decoder, which means it has the potential to corrupt a DCC signal. However, since my direct connection removed the motherboard completely, I have now concluded that these motors are simply incompatible with ESU decoders. I can't believe that someone actually thought these motors were a good idea! I concede that they are great for those of a DC persuasion, but hopeless for those of us in the DCC pond.

I have also now dismantled the loco to see what space is available for the motor. It has some tiny brass fly-wheels fitted - what is the point of such small fly-wheels - they are so small that they probably have negligible effect. Another bad design in this loco.

I'm going to research for a suitable sized Mashima-type motor to replace the rubbish motor this loco is fitted with. There seems to be a reasonable amount of space and certainly extra space can be made with a small amount of diamond cutting of the chassis block. Although I question why I should be doing this on a model of this price!

I am of the opinion that Kernow have made a really poor choice of motor.

gppsoftware
Posts: 306
Joined: Thu Mar 09, 2006 5:34 am

Re: Kernow D600 Warship

Postby gppsoftware » Sat Jul 06, 2019 3:38 am

I did some more experimentation last night.

Having installed an 8 pin socket which took the motherboard out of the equation and trying an 8 pin lokpilot in it, I decided to try a DCC Concepts Zen decoder which I temporarily borrowed from another loco.
This is the first time I have seen this loco work on DCC. It actually ran reasonably well. A bit jerky, but a massive improvement on before.
With a bit of CV adjustment, I managed to get it to run better, but it still wasn't as good as on straight DC where it is very quiet. On DCC, the motor is a bit 'buzzy'. I don't think this is the fault of the decoder.

At a guestimate, I'd suggest that this loco probably requires something like an old TCS decoder without BEMF control or a decoder where BEMF can be turned off.
It seems that decoders are unable to properly control the motor because they can't monitor the BEMF properly. Could it be that this type of motor just doesn't produce the amount of BEMF that decoders are designed to expect ?

Either way, I think I have now got to the root cause of this. It isn't the decoder and it isn't the motherboard or the polyfuse causing a problem. That fact is that the motor is a very poor choice and is simply incompatible with a number of decoders, certainly including one brand of high-end decoders - ESU.

How many other locos with this same motor have hit the market ? Do others have problems with them ?

My personal opinion is that we seem to be seeing a repeat of what used to happen in the 1980's where various attempts were being made to get better results out of straight DC control. Trouble is, I think the particular model in question has taken this to the point where it is to the detriment of DCC control and incompatible.

User avatar
Metadyneman
Posts: 1171
Joined: Wed Apr 11, 2007 9:09 am
Location: Portslade-by-Sea East Sussex

Re: Kernow D600 Warship

Postby Metadyneman » Sat Jul 06, 2019 6:09 pm

Judging by the problems you have encountered with your model and the fact that I haven't come across anyone else with the same problems (yet), I would perhaps suggest that you have been unlucky in receiving one that would appear to have been faulty from the word go. My model has worked faultlessly ever since the polyswitch issue was sorted and will run beautifully at all speeds and in either direction. It was myself and a handful of others on RMWeb who by trial & error one afternoon identified and solved the mysterious cutting out problem and everyone seemed happy once that problem had been ironed out, so I can only assume that your problem is/was a separate issue in addition to the errant polywsitch.
A bargain is something you really don't need at a price that's completely irresistible!!

gppsoftware
Posts: 306
Joined: Thu Mar 09, 2006 5:34 am

Re: Kernow D600 Warship

Postby gppsoftware » Sun Jul 07, 2019 5:34 am

Hi Metadyneman,

Metadyneman wrote:Judging by the problems you have encountered with your model and the fact that I haven't come across anyone else with the same problems (yet), I would perhaps suggest that you have been unlucky in receiving one that would appear to have been faulty from the word go. My model has worked faultlessly ever since the polyswitch issue was sorted and will run beautifully at all speeds and in either direction. It was myself and a handful of others on RMWeb who by trial & error one afternoon identified and solved the mysterious cutting out problem and everyone seemed happy once that problem had been ironed out, so I can only assume that your problem is/was a separate issue in addition to the errant polywsitch.


I think there are two issues at play, one being the polyswitch and the other being a general incompatibility with some decoders. I did see the polyswitch cutout issue occur a couple of times on my model.

I don't actually believe that my loco is faulty.

By rewiring the loco with a temporary 8 pin socket, I have removed all the variables such as the potential for a faulty motherboard and the polyswitch. That left me with a situation of directly connecting decoders to the motor. What I found was that I had a number of ESU Lokpilots and Loksound's in stock and not one of them would work. They all happily work in other locos 'out of the box'.

My conclusion is that the motor in this loco is simply incompatible with ESU decoders, which I find rather staggering since these are top-of-the-line decoders!. I am aware that some people have got them to work, but those I have been in contact with have all said that they can't stop the jerky behaviour completely.

In a 'nutshell', the problem with this loco is the motor - it is a poor choice which evidently, some decoders can't read the BEMF from to be able to control it properly. It just so happens that I use a lot of the brand that it doesn't work with!

If I had a faulty motor, it wouldn't work on DC - it actually works extremely well on DC. I can't see how a motor can be perfect on DC control and 'faulty' on DCC control. It either works or it doesn't. I believe that the PWM and BEMF used by ESU decoders is incompatible with this motor. It would be interesting to know if our DC friends with feedback controllers have any issues. My theory is that they probably have to turn feedback off.

gppsoftware
Posts: 306
Joined: Thu Mar 09, 2006 5:34 am

Re: Kernow D600 Warship

Postby gppsoftware » Mon Jan 11, 2021 6:24 am

Just an update, but I did eventually resolve the problem.

It turned out that the motor in the loco was overloading the Loksound4 and the decoder was going into a 'cripple mode' until eventually, it became damaged because it was running so hot that it hurt to touch. The polyswitch was a red-herring.

I replaced the Lok4 with a Lok5 and applied new CV settings at the bottom of the following article. Full story here: http://www.mrol.com.au/Pages/Vu/ReviewofKernowD600Warship

Bottom line is that the motor in this loco is junk, it is not properly matched with DCC decoders and it is not suitable for purpose. It is the same motor which I understand Bachmann have discarded and replaced with a new motor in the re-introduced EFE brand ex-DJ locos.

I did finally manage to get acceptable running (video at bottom of above article) but the motor just has no momentum and trying to use the decoder's momentum capabilities just conflicted with the motor again.

User avatar
Metadyneman
Posts: 1171
Joined: Wed Apr 11, 2007 9:09 am
Location: Portslade-by-Sea East Sussex

Re: Kernow D600 Warship

Postby Metadyneman » Mon Jan 11, 2021 9:59 am

Your experiences with the ESU decoders and this loco are definitely not good and certainly not something I have heard mentioned from others with this loco. I have an ESU Lokpilot Standard in mine and it runs beautifully every time I use it. As an experiment last summer I decided to let it run round the garden all afternoon for about 5 hours at a moderate speed with 10 Bachmann Mk1 coaches in tow. (This was of course after I had bridged the poly switch). The loco was obviously a little warm having travelled a fair old distance but it certainly wasn't hot or overheated and still runs well to this day.
A bargain is something you really don't need at a price that's completely irresistible!!


Return to “Other Model Railway Manufacturers and Gauges”

Who is online

Users browsing this forum: No registered users and 2 guests