Repeating loss of power problem

[pacchardon]

I got a power loss problem that does not seem to fit in with the others I have read about. I have had my layout up and running now for about 2 months. I am running 2 Bachmann DCC on Board locos with a Digitrax Zephyr Controller. I haven't had any power problems until today. One of locos will run for 15 to 20 seconds and then stop dead. After sitting there for about 5 seconds it will start up again. Then it runs again for 15 to 20 and dies. This pattern keeps repeating. The other loco is having no trouble. Anyone ever seen this before?

[jward]

that kind of sounds like a decoder going into thermal shutdown. as it heats up, it stops, then the locomotive starts again when the decoder cools. i don't pretend to be an expert on things electronic, but often thermal overload occurs when the decoder draws more current than it is rated for. thus, i'd look carefully at the locomotive to see if anything is binding in the drive train. that would cause the motor to draw more current and possibly overload the decoder.

perhaps others with more knowledge than i have would care to add their take on this problem?

[mhampton]

It is entirely possible that the mechanism has picked up some lint or dust and is causing the motor to work harder and causing the shutdown.  It is also possible that there is a cold solder joint or other marginal connection somewhere that expands and eventually disconnects with normal running.  If the decoder has some plug-in connections that you could re-seat, that might provide some relief to your problem.

[Jim Banner]

Do you have more than one throttle for your Zephyr?  If you do, there is a possibility that you have two throttles assigned to the same locomotive.  One of them could be a "phantom" throttle, that is, a throttle that was once assigned to that locomotive but was later assigned to another locomotive without dispatching the first locomotive or turning its speed all the way down to zero.  As the Zephyr steps through its slots (12 for the DSC50, 20 for the DSC51) it finds two slots both assigned to the same locomotive.  When it gets to one of these, it sends out whatever speed was last set by that throttle even if that throttle is no long connected or if that throttle has been reassigned to another locomotive.  When it gets to the other slot, it sends out whatever speed was last set by the other throttle.  So the locomotive will run at the speed you select.  Then after a few seconds, it will run at the speed set by the phantom throttle.  Then after a few more seconds, the speed you select, and so on.

The best solution is to clear the Zephyr's memory and assign the throttles again.  Clearing the memory involves setting software switches as explained in the manual.  Alternate solution is to pick up the troublesome locomotive on each of your throttles in turn, turn the speed to zero, then dispatch the locomotive from that throttle.  Eventually, you will get to the correct throttle and wipe the phantom out of memory.

Jim

[jward]

good job jim!

even though i have had a dcs50 for years i'd have never thought of that.

[pacchardon]

I checked the wheels and there was nothing binding them that I could see. So I changed the loco's address to something that had never been used to see if Jim's idea was the problem and the problem went away. So now I have to look at the manual and try to clear away that phantom slot but I am back up and running. Thanks everyone, Paul

[Jim Banner]

From page 38 of the DCS51 manual:

If you want to clear all the addresses and consist information from your
DCS51 and start over you can set Option Switch 36 to closed as follows:
1. Be sure everything on the layout is at 0 speed.
2. Press the prOg key.
3. Press the SWitCh key.
4. Enter 036.
5. Press the c/- key.
6. Press the exit key.
Your DCS51 will re-initialize with no locomotives selected and no consists set
up to run. Any locomotives that were operating at the time of the reset will
come to a stop.

The same information is shown on page 31 of the DCS50 manual.

Jim

[pacchardon]

Jim,
  I tried that and I'm still having the same problem. On the same page it says that the DCS51 runs a purge routine and removes addresses that haven't been used for awhile. In the switch table OpSw 13 can be used to extend the time btwn purges from 200 secs to 600 secs. I probably haven't gone 200 secs without using the problem address. Unless you have another idea I'll go over 200 seconds without using that address and see if the problem goes away.

Thanks
Paul

[Jim Banner]

The purge routine considers  an address to still be in use by a throttle if the speed data from that throttle was greater than zero the last time it communicated with the command station about that address.  The physical throttle might have been disconnected from the system since it last communicated with the command station.  In this case, the address will not automatically purge.

I have a similar problem with a DB150 that I bought used.  It has an address stuck in one of the slots and I have been unable to clear it out.  If I had the throttle that left it in there, the job would be easy.

Jim 

[pacchardon]

There has only been one physical throttle all along. That is the one that's part of the controller. One thing I failed to mention because it appears support your theory is that sometimes the controller has the display, 'StLo' for stealing control of the address. Might something be done at that point, like stealing control and setting the speed on the phantom address to zero.

[Jim Banner]

Now that is a good idea.  I will have to try it on my DB150 once I get it back.

Jim

[pacchardon]

Jim,
Stealing the address did not help. I still have the same problem. Oh wel. I still have room for running 19 trains which is never going to happen. So, I guess I can live with it.