Train problems

[Scottzoo]

Heres one for the clever ones, I have a class 47 from the majestic set that will happly go round and round the track 4 or 5 times and then for no apparent reason stop go in reverse a couple of pieces of track and then go forward again sometimes making it past the reversing point sometimes not.

I can only imagine its the decoder playing up as the Bon Accord made it round for an hour none stop!

If its the decoder thats the second one now one from each train!!!!!

Keith

 

[Flashbang]

Hi

Sudden reversing of direction or a complete uncontrolled run away is normally due to the decoder thinking the full DCC rail volts are DC power.  

Initally clean all rail tops and also the locos wheel treads.

Then if your DCC system allows it, turn off DC running via CV29. This cannot be done with the Select.

[Fishmanoz]

He can change CV29 Flashbang, he has Majestic set with eLink, he told us so.

 

Scott, checkout RM manual which tells you how to turn off DC running in CV29 under reading and writing CVs.

 

And why would one loco do it and not the other - some decoders are more sensitive to misinterpreting the DCC signal than others, so more susceptible to DC runaway.

 

Or you could take it back again and complain that if one works and the other not, the other is faulty and should be replaced.

[Flashbang]

My comments about setting CV29 - being able to do so and not if a Select owner were placed for general reading, not specifically the OP.  Many read the words of a forum and believe all that is written is gospel and can be done with their basic DCC systems etc. When some cant be.

 

Why the loco responds as it does, is down to one or a combination of several things.... But all DCC locos rely on the decoder receiving good data.  The causes of poor data received by a loco can be .... Dirty rail tops, poor connection in the rail joiners (fishplates), poor wiring between the console and rails, using a DC power clip or DC power track section with the suppression capacitor still inside, dirty loco wheels, where fitted - dirty rear of wheel wipers or the rear of the wheels dirty / contaminated, rear of wheel wipers not continually making full contact onto the rear of the wheel when the wheel moves slightly sideways, a soldered joint being high resistance or partially open circuit somewhere inside the loco, decoder pin damaged, decoder wire fractured and making partial connection and finally a decoder itself becoming defective. 

Doing the basics of cleaning the rail tops and the wheels are one of the two most common resolves.  Setting CV29 to DC Off is worthwhile doing too (Where possible)  e.g. read current value set in CV29 then reduce that value by 4. So for example read CV29 value as 6 make it 2 or read as 38 make it 34 etc.

[96RAF]

@FB - hear, hear...as they say in Parliament.

If the 47 had had a Sapphire installed I would have said Auto-Ops was enabled, but its not so I won't.

[Scottzoo]

Hi thanks for your replies , loco is quite new and cleaned wheels and track , changed decorders cv29 to -4 ordered new decoder and it still doesn't work so today boxed up loco plus two other decorders and sent to hornby

fishy its Keith