I have a Proto2000 HO-scale SW9 equipped with the NCE SW9-SR decoder, and it "jumps" ~1 inch whenever power is first applied to it. If this only happened when I energize the track, I could live with that; but it does the same thing if it rolls over a spot where input voltage may be a bit weak (such as an insulated-frog turnout). And sometimes it jumps in the opposite direction from where it's supposed to be moving. Seems as if something is dropping a full-strength jolt across the motor leads! Needless to say, this is a major annoyance during switching operations and coupling/uncoupling.
Does anybody have a clue why the decoder would make it behave this way, and what might be done to correct it (other than installing a new decoder)?
-Ken in Maryland (B&O modeler, former CSX modeler)
I don't have an answer but I have found that having an RRampmeter connected to my layout generally gives me a better idea of what is happening. For example, If the current draw is increasing when the loco jumps, generally means a short or bind in the mechanism.
The only time I've seen a loco change direction on it's own was when running a DCC loco in DC mode. Every time it hit an insulated frog, it reversed.
Ken
What DCC system are you useing? Disable analog in CV29 first. Second make sure the mechanisim is working good. Maybe its binding or needs lube.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
davidmbedard wrote:Check to see if you have the DC conversion diabled.
OK, I disabled it by setting CV29=034. That appeared to solve the problem - for about 1 minute, until the loco stopped responding to any commands at all...
davidmbedard wrote:Check to see if there is a slight short between the motor and the track leads.
davidmbedard wrote:Try a decoder reset.
I followed the reset instructions in the NCE manual, by setting CV30=002. This did indeed reset the CVs - but not to factory defaults, it changed every one of them to 255!
I think I must have fried the decoder at some point...
locoi1sa wrote: What DCC system are you useing? Disable analog in CV29 first. Second make sure the mechanisim is working good. Maybe its binding or needs lube.
Digitrax Super Chief (DCS100+DT400R)
mikebo wrote:... The only time I've seen a loco change direction on it's own was when running a DCC loco in DC mode. Every time it hit an insulated frog, it reversed.
... The only time I've seen a loco change direction on it's own was when running a DCC loco in DC mode. Every time it hit an insulated frog, it reversed.
Yeah, I've had that happen to me as well, before I connected the DSC100 to the layout.