Model Train Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
889 Posts
Discussion Starter #1
I've been simultaneously running a pair of Proto GP7s (double heading) on address 18 and a Bachmann Spectrum 2-8-0 on address 25. Been doing it for months.

Last week, while running both of the above, the paired Bachmann GP9s that were sitting in the engine house took off like a bat outta hay. Their address is 20. They did a little damage. It has happened again, twice, since then.

Tonight while only running the 2-8-0 on address 25, the GP9s took off again.

Whiskey Tango Foxtrot?

Put the GP9s on the programming track and change the address? Change them all to another address, then change them back?
 

·
Registered
Joined
·
940 Posts
What DCC command station are you using? Is your throttle “dual” such that you can control both your GP9s and your steam locomotive at the same time? If so, I would suggest you try releasing the GP9s from the throttle and see if that stops the misbehavior.
 

·
Registered
Joined
·
3,243 Posts
Sometimes after unplugging the power supply for the NCE Power Cab and then plugging it back in before the next session, an unprogrammed address will appear in the selection list. Random numbers, and never the same one twice.

As I run through the list to see which locomotive is missing I have to recall that locomotive's address and then everything is normal again.

I have no clue why it does this and it is random. It might not do it for a couple of months, and then a strange locomotive address will appear in the list.
 

·
Registered
Joined
·
889 Posts
Discussion Starter #4
What DCC command station are you using? Is your throttle “dual” such that you can control both your GP9s and your steam locomotive at the same time? If so, I would suggest you try releasing the GP9s from the throttle and see if that stops the misbehavior.
Digitrax Zephyr. I can run > 1 at a time, but only control 1. Each time it happens I have "called up" the GP9s on address 20 and then released/exited, only to have them "wake up" some random time later.

The really odd thing, to me, is that when the GP9s take off they're wide open/full throttle.

Sometimes after unplugging the power supply...
Right now I'm not powering off the Zephyr (unless I goof up and get a derailment at a turnout that causes a short). If I do, the next time I power it up it throws some/all of my turnouts. I don't have a turnout control/display panel (because I'll eventually use TrainController for that) so it's a PITA to figure out what position all the turnouts are in.
 

·
Registered
Joined
·
759 Posts
Stumpy:

What kind of decoder is in the GP's?
Does it happen to be a Digitrax, by any chance?

I've had similar behavior from a couple of engines that had Digitrax decoders. As soon as power is applied to the track, they want to take off at full speed. Decoders I have from other manufacturers don't do this.

The solution that I found was to DISABLE the CV setting that permits running on both dcc and regular DC. This is most easily accomplished using JMRI Decoder Pro (free software that runs under Java). You want to set both engines up for "dcc ONLY".

I can't remember WHICH CV controls this setting. Perhaps someone else will jump in with that.
 

·
Registered
Joined
·
1,818 Posts
The older basic decoders that are 'dual mode' need to have the value in CV29 reflect that the decoders will not respond to a DC signal. For long addresses, that would be a value of '34'. Google 'CV29 calculator' and you'll find several. Just use the table to determine which value you need your decoders to be for long/short addresses, and then enter the correct value into CV29 FOR EACH decoder. Once you remove DC sensitivity, the decoders won't mistake the inrush of DCC voltage to 'full DC' voltage, and then take off like scared cats.
 

·
Registered
Joined
·
889 Posts
Discussion Starter #8
Programmed CV29 so "Analog Mode Conversion" is OFF. Value = 3 if reversing direction of travel (because I run the diesels LHF) and value = 2 if not.

Thank you all!

We'll see how it goes.

 
1 - 9 of 9 Posts
Top