Kernow D600 Warship

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Bigmet
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Re: Kernow D600 Warship

Postby Bigmet » Mon Apr 01, 2019 10:16 am

D605Eagle wrote:I must say I'm super impressed with the model as a whole, it looks exactly like the prototype and runs great too. However for the price, I do think the added detail is of rather poor quality. Compare the pipework to those that come with the latest Bachmann 40, or Hornby 87 for example. They are more like the quality of pipes you got with early Heljan diesel model. Then there's the discs....OMG what a nightmare there are! 0 out of 10 for them. Very poor indeed.

I would be inclined to sit and think about these user fitted parts, to see if there is a better way. Meantime hoping that someone devises an improvement, or maybe even produces or locates/suggests some superior aftermarket alternatives.

It's a strange aspect of superior models, that small details matter more. I was initially somewhat disappointed by the Bachmann Cravens DMU (class 105) which is and remains a fine model, because Bachmann did not provide a close coupling mechanism which ISTM is such a natural feature for what are permanently coupled sets. (Hasn't stopped me buying half a dozen sets mind, and consequent on not having a close coupling mech they now have screw links and are next going to get bellows gangways.)

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Metadyneman
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Re: Kernow D600 Warship

Postby Metadyneman » Wed Apr 17, 2019 10:06 am

The second batch have now arrived at Kernow Model Centre and are being dispatched on a "date order was paid" basis. Hopefully my D600 in BR blue will be winging its way to my railway soon.
A voice from the distance said unto me "Smile, things could be worse" so I smiled and lo, things did get worse!

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Metadyneman
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Re: Kernow D600 Warship

Postby Metadyneman » Wed May 08, 2019 11:39 am

My D600 has arrived but I've encountered severe problems with it on DCC. There are reports in the "other" forum of problems with the loco grinding to a halt after a short while running under load on DCC and mine is no exception. Kernow are recommending the use of the Dapol Imperium 1 decoder in it but reports from the "other" forum seem to indicate that Loksound 5 decoders are having problems coping with the coreless motor. I have so far used a ESU Lokpilot, A Bachmann 36-557 (basically another lokpilot) a Lenz silver and a Laisdcc decoder in mine and they all produce the same fault although the laisdcc lasted a lot longer before the loco ground to a halt. No harm seems to have come to either the loco or the decoder but the loco just "shuts down" after 10 minutes or so of constant running under load. I'm in communication with Kernow models about the problem and will report back when/if I hear more. I haven't replicated the problem under DC yet but at least one person has reported the fault running theirs on DC.
A voice from the distance said unto me "Smile, things could be worse" so I smiled and lo, things did get worse!

Bigmet
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Re: Kernow D600 Warship

Postby Bigmet » Thu May 09, 2019 10:56 am

Ths shut down problem is nothing to do with DCC, but with some kind of overload protection that is installed on the model. This kicks in only when the loco is asked to pull a significant load for something like ten minutes or more (so many owners will never see the problem!). It seems this problem didn't affect the first batch of D600s released. Hopefully Kernow will be able to identify what has changed. (It could be as simple as the second batch getting bigger helpings of slightly stiffer grease in the drive trains...)

Whatever, this is one for the memory box. Four or five years from now, there will be posts like this:

"I just bought a Kernow D600, it's so clean and unmarked I don't think the first owner ever had it out of the box. While it looks perfect it cuts out afer running for ten minutes, but if I leave it a while it starts running normally again, goes for ten minutes and cuts out..."

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Bufferstop
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Re: Kernow D600 Warship

Postby Bufferstop » Thu May 09, 2019 3:14 pm

It's either something mechanical, making the motor work too hard, or something wrong with the overload protection, my money's on the mechanicals.
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mahoganydog
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Re: Kernow D600 Warship

Postby mahoganydog » Thu May 09, 2019 5:20 pm

Just as a mad thought; could it be the motor bearings? I've had new motors run OK but get hot. Lubricating the bearings made them not only run better but not get hot.

Naturally check the instructions first, it could damage the motor!
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SRman
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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.

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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.

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Metadyneman
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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 voice from the distance said unto me "Smile, things could be worse" so I smiled and lo, things did get worse!

Bigmet
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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...

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SRman
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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
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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
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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
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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.

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Metadyneman
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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 voice from the distance said unto me "Smile, things could be worse" so I smiled and lo, things did get worse!


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