kskato Posted March 29, 2011 Share Posted March 29, 2011 This one I've never heard(read) of. My new USA Flying Scotsman with DP2X-UK shorts out on my dynamis ' only when reversing '. This is on curve track- 22"/26"/28". Not every 90º. But will before you get thru another 2-3 curves he'll short. Two funny things about it--- It has never shorted going forward !( it has had several hrs running forward clockwise & counterclockwise) Also when you press the stop button it takes right off and runs, the short is gone. I can even backup the dead loco by hand in front of the spot it just shorted on, restart and it dosent short running over the same curve !? No short till it hit a curve 'just right' and shorts again!? Anyone heard of this happening ? Could it be a drive wheel, something to do with this tenders axles ?? Thanks,,, Howard Link to comment Share on other sites More sharing options...
RMweb Gold RFS Posted March 29, 2011 RMweb Gold Share Posted March 29, 2011 Coupling rod or valve gear touching the wheels possibly? Had this problem with a Hornby West Country - it was caused by the coupling rod being bent and slightly out of alignment. The problem is that this can cause a short as you've experienced, and DCC shuts down. But the loco's momentum carries it on slightly so that when you come to look closely there's nothing amiss ..... Try running the loco on its own without the tender and see if the problem persists. If it does it's the loco, if not it could be the tender. Link to comment Share on other sites More sharing options...
smokebox Posted March 30, 2011 Share Posted March 30, 2011 Take a look at the loco to tender coupling, (if it's the same as other Scotsman's) the contacts that connect to the underside of the tender are sometimes set too close together and can come into contact with the "pin" of the tender coupling which can cause intermittent shorts. Link to comment Share on other sites More sharing options...
34theletterbetweenB&D Posted March 30, 2011 Share Posted March 30, 2011 I have seen a fair amount of this on Hornby steam models, and agree with the two replies above on the places to look. Unless they have revised the construction recently, this chassis in common with many other Hornby models introduced until about four years ago has what I feel is a basic design flaw. Hornby use the loco chassis for the current path, from the pick up wiper one side to the motor connection. The 'sign peculiar' of this construction is a wire screw terminated on top of the worm gear cover. The problem this can lead to on a model with outside valve gear is that the rods can also be live to one rail, and if they make momentary contact with a wheel the other side, there's a short which at low speed can easily trip a DCC system. And as already explained, because the mechanism rolls on slightly, the contact that caused the short no longer exists when you go looking for the cause. If the tender connection is eliminated as the cause the of the problem, (i.e. the loco still shorts when running on its' own) watch the loco running at slow speed in darkness. That should enable you to eventually see a spark when the short occurs. It may be a PITA, but my method of overcoming this is to strip the chassis of all outside gear locos with this chassis design and to isolate the wiper strip from the chassis by removing a 'peg' from the bottom of the chassis block, then solder a wire onto the wiper strip as the motor connection. Link to comment Share on other sites More sharing options...
kskato Posted March 31, 2011 Author Share Posted March 31, 2011 Thanks Guys.. I'll try to trouble-shoot this weekend with your 'trouble areas' in mind. Howard Link to comment Share on other sites More sharing options...
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