I received an Athearn RTR SW1000 for my birthday over the weekend. The loco runs great...nice and quiet. I converted it to DCC using a Digitrax DH123 and it still runs good, but it does not have a good low speed start. It requires a bit of throttle to get it to move and it kind of lurches into motion. Before it does move, I can hear a bit of humming.
I'm not sure adjusting the CV's will solve the problem. I am considering removing the factory circuit board and hard-wiring the decoder in place like I did with my Bachmann 70 tonners. If I do go this route, can anyone suggest a resistor size for the light bulbs?
I'm using an NCE Power Cab DCC system.
Thanks!
Chuck,
You can adjust the V-Start (CV2), as David suggested, and improve the low-speed response of the DH123. If it still isn't up to snuff (or your standard of slowness), you may need to try a different decoder.
For excellent BEMF, I've been VERY happy and impressed with the Lenz Silver Series and Gold Series decoders. You'll probably need the Silver Mini-W (2-function) decoder, in order for it to fit under the hood. (The size of each decoder is listed in the link above.)
The low-speed response of the higher end Lenz decoders is just amazing and well worth the extra $$$. And, don't pay full MSRP for one. You should be able to find them for at least 20% off list from places like Ulrich Models, Litchfield Station, and Tony's Train Exchange.
Hope that helps...
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
TCS decoder, You can get one for aroound 20-25 bucks, Excellent BEMF
http://www.tcsdcc.com/public_html/Customer_Content/Installation_Pictures/HO_Scale/Athearn/SW1000/Athearn_SW-1000_RTR.html
Thanks everyone for the replies. I have played around with CV2 and still have not achieved what the loco will do on straight DC. I will try a different brand decoder to see if that helps. I have installed numerous Digitrax decoders in the past and don't remember having one act like this.
Thanks again!
Chuck:
When you try the replacement decoder please let us know your results.
Joe
Some of them can be had for as little as $16 each. I got some TCS-1 without the harness for that price - actually they were TSC-4 (same decoder but 4 channels on special). They have the bemf.
I've done some searches on google and you can find the TCS-1 for well under $20 if you search.
Rio Grande. The Action Road - Focus 1977-1983
davidmbedard What value did you use for cv2? Values upwards of 40 is typical for Athearns. David B
What value did you use for cv2? Values upwards of 40 is typical for Athearns.
David B
I stopped at around 20. I've decided that I'm going to remove the circuit board, hardwire the decoder and install resistors for the bulbs. Then, if I still need to, I'll install a different decoder.
I'll keep y'all posted!
I was having the same issue with an Athearn C44-9W and I adjusted the VC2 (start voltage) until I got a response at speed step 1. I had to play around with it to get it right. I think I finished with it set to either 50 or 60 and I change the momentum too, works great now. This was very helpful because I was using that loco in a Consist with an atlas that started quicker. I was able to slow the atlas down and speed up the Athearn. Hope this helps, would hate for you to do a lot of unnecessary work.
Darrell
Trainluver.shuttefly.com
cf-7 davidmbedard: What value did you use for cv2? Values upwards of 40 is typical for Athearns. David B I stopped at around 20. I've decided that I'm going to remove the circuit board, hardwire the decoder and install resistors for the bulbs. Then, if I still need to, I'll install a different decoder. I'll keep y'all posted!
davidmbedard: What value did you use for cv2? Values upwards of 40 is typical for Athearns. David B
None of that is going to change how the decoder/loco combination works. Dave mentions a CV 2 value of 40 or greater, and Darrell posted that he had to use 50 or 60. So you're still going to have to adjust it up from the 20 you stopped at, to get the loco to run the way you want it to. Personally, I'd adjust the daylights out of it first, to be sure it CAN be made to run the way I wanted it to, before I bothered doing anything else with it.
Before you do anything, set the loco on the layout and just let it run for a couple hours at 3/4 throttle, and get it broke in. I have several locos that were disappointing right out of the box, but became good runners after a good breaking in.