I am a novice at programming anything in DCC but last weekend I got adventurous and decided to reprogram all of my locos from 2 to 4 digit addressing. Not a big deal you may say!
I have a Digitrax Super Chief system with a DT400 and first attempts on the first loco were disastrous. I went word for word from the manual, but I must have done something I shouldn’t have done as after I reprogrammed my perfectly good running 80 class loco, it then wouldn’t work at all!.(It has a Digitrax DH-140 decoder fitted).
Well I walked away, read the manual again and I somehow managed to get the “test” loco running with a four digit address…great…. I then went ahead and reprogrammed another dozen or so locos and then realised the first loco wouldn’t run slow as if it had no 128 speed control. All the other locos worked fine.
Back to the manual and checked the default settings CV08/008 and 009 settings and that was ok. Checked a number of other settings like CV129, as if I knew what I was doing, but I didn’t have any success. I now have one loco the bolts out of the blocks as soon as the DT400 shows 1 on the screen!
I know that in the process of trying to get the four digit address working initially, I am sure I clicked ‘Enter’ with a CV on the screen that shouldn’t have been there, but I don’t know what that number was.
If anyone out there has had a similar experience or could tell me how to correct my error so that the 80 class can crawl again, I would be very thankful.
CV29 has to be set to 28/128 speed step when you change the address. I don't have a Digitrax system so can't tell you the procedure, but with an NCE ProCab Radio throttle there is a 28/128 speed step button that can be used to switch back and forth between them.
cacole CV29 has to be set to 28/128 speed step when you change the address. I don't have a Digitrax system so can't tell you the procedure, but with an NCE ProCab Radio throttle there is a 28/128 speed step button that can be used to switch back and forth between them.
Agreed. Somehow the gentleman has not gone on to programme CV29 to a value of either 38 or 34. All NMRA compliant decoders need CV29's input value to reflect the enabling of the new and intended 'extended' address. If you would like the decoder to respond to both DC and DCC current, use 38. Otherwise use 34.
The DT400 throttle prompts you with a Y or N when you press "enter" after pressing the new digits for the address. You have several seconds to effect this change to CV29. If you are slow, simply restore track power, enter Ops Mode, and input the correct value to CV29. The decoder will then behave properly.
Sounds like he got it running on the desired 4-digit address after the second attempt. The issue now is slow speed running. Unless he really messed around with the system settings, CV29 must now contain a valid setting for 4-digit addressing, and Digitrax outof the box defaults to using 28/128 speed steps, not 14. The decoder needs no change for 28 or 128 speed steps, that's all in the throttle. Speed step 1 is speed step 1, regardless of 28 or 128 speed steps. Likewise max is max. The difference is in how many incremental steps there are between step 1 and top speed - 128 gives you finer incremental control. 28 or 128 will not affect the starting speed of the loco, however the value in CV2 does. With an older decoder that has no BEMF and not even supersonic drive, CV2 will have to be adjusted to achieve the best minimal runnign speed on speed step 1. Make it too high though, and the loco will leap into action at the first click of the throttle knob.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
swervyn,
Are you able to do a readout of the value of CV29? For 4-digit addressing with 128 speed steps, it should be either 34 or 38 - a value of 32 or 36 means you've got the decoder set to 14-step mode, rather than 28/128 mode.
Hope this helps,
tbdanny
The Location: Forests of the Pacific Northwest, OregonThe Year: 1948The Scale: On30The Blog: http://bvlcorr.tumblr.com
Thanks Guys,
Thanks to cacole, tricky_trev, selector, rrinker and tbdanny for all your advice. I looked at each suggestion and the problem ended up being caused by CV2 as outlined by rrinker. CV2 was set to 68, I then reset to 10 and the 80 class now crawls again. Thanks again....
By the way tbdanny, I am also from QLD Oz.
swervyn
tricky_trevglad it is all running, swervyn!! However, can someone explain why a (high) value of 68 was in CV02 if a factory reset has a default value of x00 for CV02?? looks like either the factory reset never occurred, or some values were not changed....
Doesn't look like he did a reset, but he DID say he was 'pretty sure' enter got pressed while displaying a CV number that shouldn;t have been programmed. That could be where he accidently stuck a 68 in CV2.