# Digitrax Zephyr having Problems running Analog Engine.



## Daniel (Jan 9, 2011)

I'm setting up a Zephyr system on the train layout in my grandmother's store and I think everything's been set up correctly, however when I tried to run an analog engine (address 00) it runs off of the voltage provided to the track. In other words, since the track has 11V (checked with meter) for the DCC decoders to operate it will not operate the analog engine. There are no other engines on the track. 

When I turn the power on, the track status light turns green and the engine goes at what seems like full throttle. When I press power from there, the track status light goes orange and flashes while giving the walking circles (short error) and momentarily provides power to the train. I can control the train in this mode using the the throttle, however it only moves during the orange "on" flash of the track status light. By control I mean the train responds as it would if it had a decoder or if it were a DC power pack however it is intermittent.

There is nothing that I have seen in the manual describing these symptoms and I have since left work today. 

Has anyone run into this problem before and if so how was it remedied and is the track safe to run decoder equipped engines on in this state (due to the short error)?

Advice is much appreciated.


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## tjcruiser (Jan 10, 2010)

Daniel,

I'll start by saying that I am NOT a DCC guy, so take what I'm saying here as somewhat sketchy.

If I understand your question, you're trying to get a conventional DC-style loco to go on the DCC's 00 address. This is accomplished via something called "zero stretching" which essentially sends power to the track via a biased square-wave AC signal, with a net sum of the + and - portions of the signal synthesizing a quasi + DC signal. This is explained with nice clarity here:

http://www.loystoys.com/info/how-dcc-works.html

While this can work, it's a very risky thing to do with DC loco ... especially if the DC loco is sitting still on the track. The process has been known to fry DC motor, as they oscilate (at very high frequency) between the + and - voltage signals sent to it by the DCC system.

I'm hoping other more experinece people here on the forum chime in, but I would caution you about attempting to run a DC loco on your DCC in this manner. It think it's a risky venture.

Regards,

TJ


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## NIMT (Jan 6, 2011)

tjcruiser stated it really well! :thumbsup:
I would say that 3/4 of the engines out there will no work with the 00 Address. I doesn't mean there is anything wrong with either the DCC controls or the Engine. Using this mode will eventualy fry almost any engine used on it. AC Humm on a DC motor is very hard on them!
Checking the track voltage with DCC most often will give you false readings. This is a result of there being AC and DC voltages present at the same time.
What's your reason for wanting to run DC on a DCC track?
Sean


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## RGC (Dec 11, 2010)

I know this controller is the other end of the spectrum. My son's EZ command will also run a DC engine on button 10 , but if you do they either don't run or they make such a noise you know it's not doing the engine any good.


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## tjcruiser (Jan 10, 2010)

To reiterate, the 00 address is not really generating a true DC signal. It's still a stepwise square wave AC signal, but biased so that the net sum yields a + voltage tally. Though it's high frequency oscillations, any DC motor is still gonna be a high risk to frying itself via an essentially AC input voltage.


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## shaygetz (Sep 23, 2007)

In the club we called it the "Double Ot Dance" and ultimately limited analog equipment to one day out of the week. As far as I know, there has been no real improvement over the years to the function.


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## Daniel (Jan 9, 2011)

Thanks for everyone's advice.



NIMT.COM said:


> I would say that 3/4 of the engines out there will no work with the 00 Address.
> 
> What's your reason for wanting to run DC on a DCC track?


It's a display in a store. I'd like for it to be able to run both types of trains. A given analog train may see twenty or thirty minutes of run time during a busy week outside of the Christmas season, we generally use the O-scale stuff when kids come in.

Any idea why only certain analog trains work with DCC controllers?


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## NIMT (Jan 6, 2011)

To put it in a simple form the motor design and lighting design effect this.
The Impedance of electrical devices in them effects the way the signal is interpreted. 
You can set up the display to run both DC and DCC just not both at the same time. Or better yet parallel tracks one DCC the other DC.
Sean


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