RMweb Gold Barry Ten Posted March 13, 2013 RMweb Gold Share Posted March 13, 2013 Hi all - not sure where this query strictly belongs, as it may or may not be a DCC issue - but here goes. I have an N scale Kato E8 which has always been a great runner on DC. I put a digitrax decoder in it a couple of years ago and again it has run very well. But in the last month or so the model has begun to stop after a few minutes of use - usually just 3 - 5 laps of my layout. The shell feels warm and if I allow the loco a minute or two to cool down, off it goes again. I've given the engine a thorough dismantling, checked for general gunge and so on, and applied a tiny amount of lubrication to the motor spindles and gear trains but this has not made any difference. Kato themselves suggest that their models will need little if any lubrication. This leads me to conclude that the motor or decoder must be overheating, or some combination of both. The top speed of the engine is also nowhere near as fast as it used to be. I don't have another E8 or another digitrax decoder of the same type to try a swap unfortunately, or I could try and isolate whether the fault was in the motor or the decoder. Any have any experience with this sort of thing? Link to comment Share on other sites More sharing options...
RMweb Gold roundhouse Posted March 13, 2013 RMweb Gold Share Posted March 13, 2013 I haven't had this happen but have had a fair few of the more recent Digitrax decoders fail in fairly new Kato locos, particularly in the ACe70Macs, AC4400's. First of all they stop running in one direction then eventually the loco will stop, shorting out the layout. Older Digitrax in older Kato locos generally havent been a problem. I haven't sent them back to Digitrax as i dont know where and when I bought each decoder, so without a purchase date they probably wont be interested. Ian Link to comment Share on other sites More sharing options...
34theletterbetweenB&D Posted March 13, 2013 Share Posted March 13, 2013 Greater heating now than in the past, means more current is being drawn than used to be. The fact that you observe it no longer runs as fast, and have got no improvement by a light lubrication to the mechanism (and presumably consider the mechanism to have no obvious dragginess or mechanical defect as otherwise this would have been mentioned) points at one of two leading possibilities. The motor is deteriorating. Could be brushes worn close to end of life for example. The decoder is malfunctioning in some way. I would want the decoder out, and to test the chassis current draw and operation on regular DC. If the current draw on DC is as it was before the decoder went in, and the loco runs at a 'correct' maximum speed, and will operate long term without heating that clears the motor and chassis. Link to comment Share on other sites More sharing options...
Adrian Wintle Posted March 13, 2013 Share Posted March 13, 2013 My DCC equipped units don't get enough continuous use to be a good indicator*, but I did pick up an older Kato unit that got hot on DC while I was debugging it. One of the issues was that it needed lubrication, but the primary issue was a bad brush on the motor - changed that and it ran much better (and cooler). With the old brush (or lack thereof - the brush and spring disappeared into the workroom carpet when I disassembled it, so I don't know what shape it was in), the brush cap got too hot to touch after a few seconds of running. Note that the other brush on this loco was fine. *too many locos, not enough layout... Adrian Link to comment Share on other sites More sharing options...
RMweb Gold Barry Ten Posted March 13, 2013 Author RMweb Gold Share Posted March 13, 2013 One of the issues was that it needed lubrication, but the primary issue was a bad brush on the motor - changed that and it ran much better (and cooler). With the old brush (or lack thereof - the brush and spring disappeared into the workroom carpet when I disassembled it, so I don't know what shape it was in), the brush cap got too hot to touch after a few seconds of running. Note that the other brush on this loco was fine. One of the posts on the US forum suggested it might be the brushes but to be honest I don't rate my chances of inspecting/cleaning them without losing something - that's what usually happens when I go near brushes. Link to comment Share on other sites More sharing options...
Adrian Wintle Posted March 13, 2013 Share Posted March 13, 2013 One of the posts on the US forum suggested it might be the brushes but to be honest I don't rate my chances of inspecting/cleaning them without losing something - that's what usually happens when I go near brushes. I would suggest doing the final disassembly in a box. The brush cap is held on by three wings. It is reasonably easy to release one wing (using a tiny screwdriver) without the cap coming completely off. It is when you wiggle the cap to release the other two wings that the bits go walkabout. The Kato brush set contains two brushes, two springs, and two brush caps, so I guess they expect this. Reassembly is quite easy as the brush cap has an indent that will prevent the spring from escaping while you press it on. Brush cap removal is non-destructive, so I reused the brush cap on the last one. Adrian Link to comment Share on other sites More sharing options...
RMweb Gold Barry Ten Posted March 13, 2013 Author RMweb Gold Share Posted March 13, 2013 I would suggest doing the final disassembly in a box. I was thinking of one of those sealed cabinets they reach into with gloves to handle toxic substances... Link to comment Share on other sites More sharing options...
Adrian Wintle Posted March 14, 2013 Share Posted March 14, 2013 I was thinking of one of those sealed cabinets they reach into with gloves to handle toxic substances... That's for assembling Microtrains couplers... Link to comment Share on other sites More sharing options...
RMweb Gold Barry Ten Posted July 7, 2013 Author RMweb Gold Share Posted July 7, 2013 Thought I'd pop back with a progress report on this one. I got some new Kato brushes from ebay and managed to swap out the old ones. I had my doubts as the old ones didn't look visibly different to the ones I was replacing, but I replaced them anyway and reassembled the loco. To begin with I convinced myself that it had had a beneficial effect on the running but as soon as I popped the body back on the old overheating problem came back. So it's not the brushes, and I'm a bit stuck now. I could chance ordering another decoder and see if that makes any difference - I suppose if it doesn't the only thing left is to swap the motor. Edit - I've bitten the bullet and ordered a new decoder. It would have cost about the same to order a new motor, so it was swings and roundabouts as to which to try first. Link to comment Share on other sites More sharing options...
RMweb Gold Barry Ten Posted July 10, 2013 Author RMweb Gold Share Posted July 10, 2013 The plot thickens! New decoder installed, made no difference. Fortunately these digitrax decoders fit in other Kato models so it can be put to good use but now I suppose the only thing left to change is the motor. I've checked the drive train, all is free-running as far as I can tell. Bit of a b*****r really. Link to comment Share on other sites More sharing options...
RMweb Gold Barry Ten Posted August 1, 2013 Author RMweb Gold Share Posted August 1, 2013 If anyone's still interested in the saga, I finally ordered a new motor from Kato USA's supply department. Only took a week or two to arrive so a pretty good service. Took me an evening to install it, though - I had terrible trouble with those little motor tags and the retaining clip that Kato use. What I find is that after you've taken it apart a few times, the clip on the Kato mechanism starts becoming looser and it becomes very hard to get the contacts to work properly. Or maybe it's just me? Got there in the end, though and the engine is now rocketing along. The upshot is that I ordered new brushes and decoder unnecessarily, but they'll be used at some point. I still don't know why the old motor died (or was dying) the way it did since the model hasn't had any particular abuse over the years. Link to comment Share on other sites More sharing options...
RMweb Gold roundhouse Posted August 1, 2013 RMweb Gold Share Posted August 1, 2013 I have had a couple of newer released Kato locos where the motor failed after very little use. One was a Kato Amtrak P42. I could have sent the loco back to the retailer but after running in I soon weather and detail most of them. As you say Kato USA are very good sending out spares and the prices are pretty good too. Glad you have sorted it. Ian Link to comment Share on other sites More sharing options...
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