I received my second DCC locomotive yesterday. It's a Bachmann GP-9. It is a nice loco and runs well except that it only started at level 7 on the throttle. I changed Cv2 so it starts at level one. At that setting, it really crawls. The problem is that it will maintain that crawling speed up to level 7. I understand that, by changing Cv2, I only changed the level at which the loco starts. I didn't improve the speed curve. How can I get a better (read more progressive) speed curve?
Guy
Modeling CNR in the 50's
Guy,
You can either 1) do it manually by entering increasing values in CV67 thru CV94, or 2) download Decoder Pro and use the slider bars to adjust them. You'll need the NCE USB interface with your Power Cab in order to do that.
If manually, you can use your Power Cab to read the values of CV67 thru CV94 on your programming track. Write them down in order and note how they change and in what increments. Once you have the defaults written down, you can then play around with the values of each CV and see how your locomotive responds.
It's a great way to learn. If you completely mess things up, a reset will return your decoder to factory defaults.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Must be a quirk of those decoders Bachmann uses, normally adjusting CV2 to get a better start DOESN'T mean that speed remains constant from start up to whatever step is the equivalent of the setting in CV2, they usually just acclerate evenly from the start point to max throttle. It almost sounds liek maybe you have speed tables enabled but one isn;t set, so for every step below the speed set by CV2, it just uses the current speed.
Check your value for CV29. If NOT using a speed table as Tom described above (and setting CV2 means you do NOT need to use a speed table), subtract 16 from the current value.
Yor current possible settings vs what it should be:
If 18, make it 2
If 19, make it 3
If 22, make is 6
if 23, make it 7
If 50, make it 34
if 51, make it 35
If 54, make it 38
If 55, make it 39
That should cover most possibilities. If you decide to use speed tables like Tom described, do the reverse so that the speed table actually works.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thank you guys. I will try this as soon as possible. With your help & Internet, I learned a lot today on Cv29 and speed tables. Going from DC to DCC is a whole new adventure in many aspects.
Thanks again.
P.S. did I ever tell you that there will be many more questions to come?
I have the Bachmann GP-7 with DCC On-Board and have the same results. Looking at the Bachmann Two Function Decoder specifications at http://www.bachmanntrains.com/home-usa/ez_content/1_Amp_Decoder_Instr.pdf leads me to believe that this decoder does not support speed tables. The only CV setting for controlling speed appears to be the CV2 starting voltage setting.
My Layout Pics
I'm not sure that's the same one they still use on new releases. That looksliek the old VERY junky Lenz-made one they used to use. A decoder so bad Lenz didn't even offer it under their own name any more. Bachmann has the gall to offer it as an aftermarket item at $19.95 - that was a decoder with a feature set about what deocders had in the earliest days of DCC and was woefully out of data - and $20 for it was REALLY bad when the far superior in every way NCE D13SRJ is available for $12 each in a 10 pack.
I was under the impression that the newer Bachmann motor-only decoder was a completely different one and at least somewhat better than the old junker. Of course, if this is an older run Bachmann loco - then yeah, it has that decoder and no amount of messing around will make it better. Replacement with a quality decoder is the best option.
RogerThat I have the Bachmann GP-7 with DCC On-Board and have the same results. Looking at the Bachmann Two Function Decoder specifications at http://www.bachmanntrains.com/home-usa/ez_content/1_Amp_Decoder_Instr.pdf leads me to believe that this decoder does not support speed tables. The only CV setting for controlling speed appears to be the CV2 starting voltage setting.
The bachmann GP-9 is equipped with the same decoder which they call E-Z Command two Function Decoder. So I am planning to replace it as Randy recommended.
It seems, once again, that I got what I paid for.
Thank you all.
Well, it's not horrible, (the decoder is, the loco isn't) - so the total with decoder is less than many similar locos without decoders. Even considering the decoder is disposable, the overall price is still decent.
Take the shell off and look. If the insides resemble the pictures in the instructions here: http://www.ncedcc.com/component/virtuemart/?page=shop.product_details&flypage=garden_flypage.tpl&product_id=51&category_id=13
give this decoder a try. It's made for Bachmann diesels, and while not a direct drop in (you have to solder the wires on), it fits in place of the stock board. And includes nicer LEDs for the headlights. ALso pay attention to the step about removing the capacitors. It will run MUCH better without them.
Randy,
I originally bought that locomotive to be able to run my layout while waiting for someone else to install DCC decoders in my DC locomotives. Ironically, it seems that this will be the first conversion project I will attempt.
Thank you for the reference and all those advises.
I don't know what Guy's GP-9 has in it, but my Bachmann GP-7 has an 8 pin plug. I would think the NCE D14SRP would be the best fit for it. http://www.ncedcc.com/images/stories/manuals/d14sr.pdf
Also, I agree that for the $45 dollars I paid for this locomotive, it was a very good deal.
I didn't open it yet, so I can't tell if there is an 8 pin plug. And I agree with you that for the price it was a good deal. I regret nothing but I would like to put a better decoder to improve the performance at slow speed.
Thank you for the information.
I also paid $45 for mine. But I don't have any decoder issues. I adjusted the seed steps by interfacing my digitrax zephyr with my PC to use Decoder pro. If make programing a lot easier!
Here is the link: http://jmri.sourceforge.net/
Hope is works!
Marcos