Spooky

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Aerojet

Active Member
Problem, I just can't get a handle on. Have Digitrax Zephyr, it is a good 10 years old. Now - running train 1 on it's address, there is a problem car which uncouples. No problem here, throw the throttle into 0 and the direction into brake and attend to the train problem.

Train 2 is on another track not associated with the main line and sitting there, quietly until I am working on train 1 -=-

Suddenly it comes to life, and moves out at full speed - right thru the switch -- and screaming around a curve rams the back end of what I am trying to fix.

Shut off all track power, and clean up the now double wreck.

So what gives? Why did train 2 suddenly find power, it was not dialed into the unit? I had not changed the loco number.... OR why when both the throttle at 0 and the direction at brake is this unit suddenly screaming out of the siding and onto the main line???

Problem # 1 with the S4 has been fixed - reset CV29 to 2 and it went away.

Ghost train? Or is my DCC unit dying?

Aerojet...
 

KB02

Well-Known Member
I had a similar issue with the sound on one of my locos (loco 1). When I ran a completely different loco (loco 2), and only on certain parts of the track, the sound would crank up on loco 1 like it was running at full throttle yet it was sitting still. If loco 1 was running when I started up loco 2, it would stop and the sound would crank up again.

Loco 2 was an old(er) train that had an old 3 pole motor. After I did a motor swap to a newer can motor, the problem went away.

I have no idea why this happened, or why it stopped. Were either of your locos DC-to-DCC converts like mine were?
 

bnsf971

Gomez Addams
Staff member
You need to set CV29 to allow the decoders to recognize DCC signals only. The momentary power loss from a short confuses the decoders, and when they come alive after the power interruption, they see 12 volts, and it's off to the races.
 

tootnkumin

Well-Known Member
Staff member
Thanks for that explanation Terry, have seen that recommended and am now applying that as a DCC standard, but never a proper description of the process as to why it could occur. I'll write that out as a note for my club, as many like to retain the dual DC/DCC capability.
 

new guy

Active Member
I have two identical Athern Genesis SD45's down to the cab number and ONE of them LEAPS backwards at speed step 20 and just as quickly comes to a stop all by itself when track power is turned on! It did not always do this, just in the last few months, the first year it ran as it should and WHEN it should!
 

Aerojet

Active Member
Thanks for the responses. Unfortunately all units were bought as DCC / sound only. I have only one DC unit running as "00" -- as far as CV 29 they are all set at either 2 or 6 as far as I know. Terry's answer seems to be the best one, although i don't know how to fix that one either - as I said the CV 29 is set, so???? Is there another CV which would control this? I have the analog section turned off with 2 or 6 so, it should not happen. ALL I can say is "spooky" when it does.

One other thing the S4 Saturday night was acting funny. it kept on switching on and off, not moving but starting up and then shutting down over on the parking track by the station. The caboose connected to it has a light in it and it was not flashing which would show something electrical going on. AND yes I am aware of the 14 vs 28 step problem which is why I am on 2 or 6.

Still I wonder if the DCC unit is going nutso like an old computer does? Could be as well. One never knows with these things what may happen next...

Thanks for the comebacks...

Aerojet
 

bnsf971

Gomez Addams
Staff member
Thanks for the responses. Unfortunately all units were bought as DCC / sound only. I have only one DC unit running as "00" -- as far as CV 29 they are all set at either 2 or 6 as far as I know. Terry's answer seems to be the best one, although i don't know how to fix that one either - as I said the CV 29 is set, so???? Is there another CV which would control this? I have the analog section turned off with 2 or 6 so, it should not happen. ALL I can say is "spooky" when it does.

One other thing the S4 Saturday night was acting funny. it kept on switching on and off, not moving but starting up and then shutting down over on the parking track by the station. The caboose connected to it has a light in it and it was not flashing which would show something electrical going on. AND yes I am aware of the 14 vs 28 step problem which is why I am on 2 or 6.

Still I wonder if the DCC unit is going nutso like an old computer does? Could be as well. One never knows with these things what may happen next...

Thanks for the comebacks...

Aerojet
You can use this configurator to calculate the value of cv29:
http://www.2mm.org.uk/articles/cv29 calculator.htm
 




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