Back EMF

If you are using the user defined speed table, turn off BEMF.  I've had that kind of problem before and turning BEMF off fixed it.  BEMF doesn't seem to play well with the user defined speed table.  I've suggested this to a couple friends in the past and they were amazed  at how performance smoothed out.

Assuming

that the loco ran very well under DC before the conversion?

Yes it did I try some things

Yes it did I try some things with speed tables & dither Not really a change !!!!

Could the brushes be bad in

Could the brushes be bad in the motor ????

Back toward the begining.

Do you have a locomotive that runs well on that stretch of track

Are your wheels clean.  It never hurts to clean the wheels by the paper towel on one truck at a time method. 

You could try running the locomotive on the motor leads (disconnected from the decoder) and a 9 volt battery not using the decoder and with the track power OFF.  If it works try two 1.5 volt, batteries in series. Then a single,to,simulate the low voltage issue.

Let us know,if this works...

Nick

PS I'm interested in the Roco/Atlas EMD units.  I do not have one and have converted a lot of newer one to LokSound DCC.  Eventually some pictures would be nice.  Thanks! 

What did TCS recommend ?

Just so no one doubles up and to help eliminate possibilities. 

I was wondering what the kick voltage settings are.

This is what TCS suggested

This is what TCS suggested !!!!! I try these & if I did them right it didn't help !! I will try these again when i get some-more time !!!! I will try to run in DC again !!! wheels clean !!!! Like I said runs good at like speed step 4 or 5  1,2 ,3 some times it starts slow but then starts JERKING !!!!!  i will try them again but starting to think motor issues !!!                                                                                                                                           There are three options for you that I can think of which may resolve your issue.

The first of these options is to activate User-Loadable Speed Tables by programming CV 29 with a value +16 of its current value. You may then program CV 67 - 94 to set your speed step voltages. I suggest setting CV 67 to 1 and 68 from 2-10

Your second option is to enable an outdated but customize-able motor control system called dither. To do this, subtract 1 from the value in CV 61. Dither can be customized by CV 56 and 57. Refer to the TCS Comprehensive Programming Guide for a detailed description of dither and these CV's.

Another option is exclusively for if you know your locomotive has a 3-pole motor. If it does, you can enable the special BEMF algorithm by adding 1 to the value in CV 182. You can try this anyway, but you may see worse performance if you do not have a 3-pole motor.             Any help appreciated!!!!!  RC 

This is what it looks like ,

 This is what it looks like , I got it hookup to run dc will not move less then 2.5 volts , looks like this motor will not run at low speed !!! 

Another couple of questions...

After it starts to move is it smooth or jerky?  When you increase the dc voltage (throttle) a little at a time does it remain smooth or become jerky at certain levels?  The answers will tell you if it is likely to be a motor issue.  You've  made a good diagnostic move now.

Nick

The motor doesn't run under

The motor doesn't run under about 2.5 volts you can feel the power there but it doesn't move around 4.5 volts it runs smooth , in dcc step 1,2,3,4 moved but jerked bad !!! step 5& above  ran smooth !!! They make a brush set for this motor, But I like to know could this be a problem ????  I remember the old ho race cars something similar happen like this & i replace brushes on them !!! but I don't have any experience with these motors don't know if it will help ???? All those changes I did in DCC  with CV"s change the speeds  , But  never stopped the jerking !!    Never jerky at higher voltage  or speed steps!!!!              RC

Now that we've established a dc running profile....

If you are happy with the running using dc then next we should simulate the dc profile with the DCC decoder.  First, I would reinstall the decoder.  Next set the decoder back to factory original settings (default). TCS says for CV8 enter 2.  Next we'll increase the starting voltage to about 4.5 volts.  I'm reading the instructions now to figure out how to do that.  Let me know when you've got the factory reset step done, please.  We'll proceed from there if you wish. (81)

Autodetect is a good possibility to diagnose also, I think.  Don't worry about that now.

Nick

The one problem i see is I

The one problem i see is I can't get it to run at a slow speed even in DC 4.5 volts it's going to fast already !!!! In DCC it ran slower but it was so Jerky !!!  I try to fool around with cv 2 it either didn't move or shot like a rocket !!!    Maybe something wrong with the low end of the motor ??? I appreciated you trying to help !! RC

Motor quality

Motors used back then generally had two speeds:  Dead stop or warp speed.  That's why re-motoring with a better quality one was so popular.  Unfortunately DCC can not improve on that.  I think you have a lost cause here.

@ RC

Hi RC,

I think Rick's advice is probably correct.  I went to the Atlas site and dug around for a replacement electric motor and couldn't find an electric motor on the site anywhere.  You might try to email their customer service and see if you can get a motor.  If you are good at making things work, take any newer non-Roco motor for an HO scale locomotive and swap it out for the one that's in the locomotive now.  The newer motors should make your locomotive run smoothly.  The new motors are very good.  I'm sure that it wll not be a direct fit and some modifications will be necessary but it might be a fun project for sometime in the future.  If you keep an eye on eBay and stay away from the early Atlas/Rocos you can probably get a reasonable deal on a newer Atlas locomotive.  The newer Atlas locomotives are very good.

As a further thought, if you contact Atlas you could ask them what the Model numbers of the post Rock era were or started at so that you could avoid another trouble maker.  Reputable dealers and sellers will list the model number.

Hope this helps.

Nick