Decoder problem....

Model Railroader General Discussion (Model Railroader)
1

I was given a neat little Doodlebug, complete with rear lights by a life-long friend who recently passed away. The unit is DCC controlled, and has a Lentz decoder installed which was completely functional when it was given me. It had the address of 06, but I cannot get it to run, or “power on” in any way.

I have a Digitrax Zephyr, but always thought most decoders will operate with any DCC controller. I tried to reassign a different address of 03, but that did not work. It has never ran on my layout, and I cannot figure out what to do next.

It would mean a lot to have one of my friend’s unit’s operationing on my layout, so I am asking for any and all suggestions. Thank you…

2

Yes, absolutely, any decoder (well, any NMRA-compiant decoder) should run with any NMRA-compliant system.

I’d first check for a mechanical problem, like dirty wheels, broken pickup, etc.

Do you know what kind of decoder it is?

Can you read it on the program track? If so, get CVs 7 and 8, then check this cross-reference from Tony’s: http://www.tonystrains.com/technews/dec_rescue.htm

That will tell you not only what it is, but how to do a reset. (As you’ll see, many will reset if you put 8 in CV 8).

Do the reset, on your program track. It may or may not “jump” in confirmation.

It should then operate on address 3, and you should be able to re-program it.

If you can, then try changing something other than the address to see if it will accept that.

Then try a different short address, like 4.

I have no idea how a Zephyr works, so don’t know if there’s an easy way to set a long address, if that’s what you need to do. My NCE will set them very easily, either on the main or program track, but some systems wont. But if you get it changed to 4 or some other short address, then you know the decoder is probably ok.

Let us know how you do with this much, and what you found in CVs 7 and 8. Somebody here will be able to help with the rest.

By the way, here’s a great site about many things DCC (but not the Zephyr, unfortunately), that’s actually understandable: http://www.members.optusnet.com.au/nswmn2/DCC.htm#Contents

3

Pondini…

Thank you for your reply. I have done the mechanical check (track, wheels, etc.), and I can read it on the program track. It shows the address is 06. I checked CV’s 7 and 8, CV-7 was 7, and CV-8 was 99 (d099) for my LENZ decoder.

I went to the Tony’s Trains link and it shows that the Mfg.'s ID in CV-8 should be 99… the CV for reset + value is 33. After doing the reset, it failed to power-on in address 03, or the old address 06.

This is where I will stop until I get some more input (hopefully, from the MR forum members…) but I will cruise the membersoptusnet link you suggested I check out.

Thanks again… Iron Goat

4

Well, at least you know the engine and decoder are getting power, and it responds on the program track. That’s major progress, believe it or not!

I know nothing about the Digitrax system, but I wonder about the address of “06”. Does it normally show a leading zero for a one-digit short address?

If the reset worked, it should now have short address of 3. Does your system allow you to specify “3”, or do you have to enter “03”?

Just a thought by a Digitrax ignoramus . . .

5

Anytime you are in program mode with the Digitrax, you get a 3 digit address, because there is AD 2 and AD4 (2 digit address, and 4 diget address), but because AD2 supports all values 1 thru 127, you get three spaces (while in PROGRAM). Once, the values are locked, and you are back on the main track, with power on… the loco address is shown as 03, 06, etc., and all you have to punch in is 3, or 6 to get the 03 or 06 display. (I’ll bet that’s clear as mud…)

The address following reset was 003 in program, and 03 in normal run mode… and if anyone is a DCC Ignoramus, it’s me !!!

I have also lifted off the cab body, and all wires are intact and no burnt wires… other than that, I remain stumped. Thanks again… Iron Goat

6

Instead of trying to read and set idividual CVs, try resetting the decoder’s address with your DCC system and see if that works.

The decoder may be “locked” to prevent changes to CVs or address. Download the latest decoder documentation from the Lenz North America web site and see if they can be locked, and what the CV number is that is used to unlock it.

A TCS decoder, for example, can be unlocked by programming CV 15 with a value equal to CV 16, and CV 16 has a default value of 1. Programming any other number into CV 15 locks the decoder.

7

Iron Goat,

The Lenz/Atlas decoders are notoriously difficult to program with a Digitrax Zephyr. I had a few of the low cost Lenz decoders and a couple of Bachmann decoders that would not take programming from my Zephyr. Atlas and Bachmann decoders are actually Lenz decoders in disguise.

In desperation I contacted the technical people at Digitrax. They suggested that I place a 1000 ohm, 1/4-watt resistor across the programming track. This ‘fools’ the Zephyr into increasing the program signal output.

Whatever it does, it worked. Since using this little trick I have not had a problem programming Lenz/Atlas/Bachmann decoders.

I have a picture of my ‘programming resistor’ in place on my programming track posted on my website. Once on site go to the ‘How’d You Do That’ page and scroll down.

I’m certain this little trick will solve your problem, unless you have a ‘dead’ decoder. Unlikely IMHO.

Good luck!

8

Thanks, I try that as my next step… Iron Goat