After a recent show, I have three engines that immediately take off in reverse when placed on the track. They do not respond to any commands. Is this a CV thing (which I cannot understand from reading the manual) or is it a fried decoder? Thanks in advance for any help.
"Rogue" locomotives are often responding to DC on the track. Be sure address 00 is set to speed=00. For the locos in question, check to see if CV29 allows DC operation. This is normally the default when CV29 is set to 006/x06. You can disable analog conversion by subtracting 4 from the CV29 value (i.e., set CV29 to 002/x02). You can also disable DC operation from the command station. For Digitrax command stations, this is done by setting OpSw #20 to "c". If that doesn't work, try a rubber mallet.
As Doug stated above, disable the Analog DC operation. Allow on DCC operation in CV 29 and your "runaway" loco's will stop happening. Stay cool and run steam.....
These locos were running fine on DCC before the show, but sometime during the show the engines started doing their own thing. I have tried reprograming them, but they continue to run backwards at full speed when placed on the track. I have tried to understand the manual's explanation of CV29, but I'm still lost. Is it possible that CV29 got changed sometime during the show without anyone being aware of it? We were using 300 and 400 throttles with a Digitrax Super Chief. Why would these three engines be behaving this way when no others are? Simply plugging the throttles back into the loconet does not recapture these "rouge" engines. From my experimenting, I believe that the problem has something to do with the CV29 setting or a faulty decoder. I have tried setting CV29 to 06 (default setting), but I am not 100% sure that I have done it correctly. Do I still need to disable the analog DC operation? If so, how do I go about it? I should have some more time to work on the problem this weekend. I'll be working in the direction suggested by Doug. I'm just not sure that I can make sense out of the Digitrax manual's explanation of CV's.
You should be able to stop the runaways (for now) by selecting address 00 on the throttle and setting speed to 00, although if anyone ever sets 00 to a non-zero value in the future, your analog-enabled locos will again take off. That's why analog conversion should be disabled, either in the loco decoder via CV29, and/or at the command station (OpSw #20=c). As to the manual, Digitrax recognizes that a picture is worth a thousand words, however it seems that they chose to go with the words. Here's a link that may be helpful: http://home.neo.rr.com/mrwithdcc/bitmask.html Remember that each of the 8 bits that comprises CV29 controls a feature (such as Normal Direction of Travel (Bit 0) and 2/4 digit adressing (Bit 5)) as well as having a value (1,2,4, 8, 16 etc.). By selecting the features you want enabled and adding the values of the related bits, you will get the CV29 value in decimal. Hexadecimal is often preferred to decimal in many cases because it can represent in one digit the full range of values of a group of four bits. Two hex digits (0 through F) can then be used to represent the 8 bits of the CV. If we had been born with 8 fingers on each hand, we would all be working in HEX anyway (1,2,3,4,5,6,7,8,9,A,B,C,D,E,F (carry the one) 10,11,12...1E,1F, etc.). Doug
A friend brought over his laptop computer which has Decoder Pro (?) or somesuch software for debugging. We managed to get the engines back under our control. Apparently, the problem had to do with the decoders getting somehow switched from 4 digit addressing to 2-digit addressing mode (keep in mind that I know virtually nothing about which I am speaking) if that is possible. Anyway, the good news is: Problem solved on the locomotives that were speeding away in reverse. Now, as for the locmotives that were dead...they still are! Problem probably fried decoders. Further testing to follow. Thanks again to those of you that offered assistance.
