Atlas C-420 Issue

[BCR751]

I recently picked up a couple of Atlas C-420's.  I put them on the track to test them today and noticed that both locos require much higher speed steps to start and to run at prototypical speed than any of the other locos that I have.  I believe the decoders in these units are made by Lenz.  Is this issue common to Lenz decoders or could there be something else wrong with the units?

Doug

[robwill84]

If they're old enough to have the Lenz decoders the grease on the gears is possibly gunked up.

[Iain]

My Piedmont and Northers were over-greased, and the grease had gunked up (it had also seeped out all over the place in the box).  Much cleaning and a light lubing later, and they were fine.

[peteski]

My Piedmont and Northers were over-greased, and the grease had gunked up (it had also seeped out all over the place in the box).  Much cleaning and a light lubing later, and they were fine.

I serviced a pair of those locos which had this exact problem.  Full disassembly, cleaning and re-lubrication (sparingly) took care of the problem.  The ones I serviced also had cracked universal couplings on the motor shaft.

[mecgp7]

Yep, a lot of extra lube. Don't forget the wheel cups where the points of the axles sit. I had a loco with so much lube that there was little conductivity.

[BCR751]

If they're old enough to have the Lenz decoders the grease on the gears is possibly gunked up.

I thought of that.  I took them apart and there didn't appear to be an excessive amount of grease either on the gears or the drive train and I can't  find any source of binding either in the drive line or the trucks.  I cleaned them up and re-lubed the drive train at the idler blocks using Labelle 108.  I then re-assembled both and they still run very slowly.  For example, my Kato SD40-2W runs at what I consider prototypical speed (~35 scale mph) at speed step 10 on my NCE PowerPro.  So do most of the other locos I have.  The two C420's don't even start moving at that setting.  To get them to 35mph requires a speed setting of 29 !  I think I'll fire up DecoderPro and read some speed related CV's

Doug

[peteski]

Unless a full speed table is enabled then CV2, 5, and 6 are what you should check first. You can easily do that on the NCE programming track.  Setting them to zero should disable them and allow for full voltage to reach the motor.

[Rich_S]

Unless a full speed table is enabled then CV2, 5, and 6 are what you should check first. You can easily do that on the NCE programming track.  Setting them to zero should disable them and allow for full voltage to reach the motor.

Pete, I was under the impression that the Lenz decoders used in Atlas locomotives did not support CV5 (full value) and CV6(mid value) settings? According to my Lenz LE063XF documentation that was downloaded from the Atlas web site, CV5 and CV6 are not user adjustable. The only CV that are user adjustable according to this documentation are: 1,2,3,4,7,8,17,18,19,23,24,29,50,51,52 and 67 through 94 which is the speed table. 

http://www.atlasrr.com/pdf/LE063XF%20Manual_Atlas.pdf

[peteski]

Pete, I was under the impression that the Lenz decoders used in Atlas locomotives did not support CV5 (full value) and CV6(mid value) settings? According to my Lenz LE063XF documentation that was downloaded from the Atlas web site, CV5 and CV6 are not user adjustable. The only CV that are user adjustable according to this documentation are: 1,2,3,4,7,8,17,18,19,23,24,29,50,51,52 and 67 through 94 which is the speed table. 

http://www.atlasrr.com/pdf/LE063XF%20Manual_Atlas.pdf

It has been a while since I dealt with those ancient decoders. Sorry that I steered you wrong way. So, from the decoder side, the only thing left I guess is to check if the speed table is set up in a way that slows the loco down.  If that is not it then the problem is mechanical in nature.

[rrjim1]

Atlas locos with a scale speed motor will require a lot more speed steps than say a Kato loco. If you are comparing them to other Atlas locos with scale speed motors and they require a lot more speed steps, then yes something is wrong. My guess is they are just fine!

[Mike C]

Supposedly if you set CV 94 of the speed table to a number low enough , and then set each lower CV to a value just a bit lower , You should be able to tame the high speed loco .  I've messed around with a speed table in Decoder Pro a couple days ago , trying something like this, but was unable to get a satisfactory result . User error , I'm sure 

[BCR751]

I think the best way to solve this problem is to install a couple of TCS decoders 

[jeffstri]

If you're seeing the same problem in both C420's the decoder seems unlikely to be the cause. I have a dozen Atlas locos with the LE063XF, 9 of them with "scale speed" motors and 3 with the older high speed motor and I've never seen anything like you describe.  Because the older motors have a much higher top speed than the scale speed ones, I use speed tables in all of them. All of them start to creep nicely at CV67 settings between 5 and 15, and achieve prototypical maximum speeds with CV94 settings between 60-120 for the older motors and 175-200 for the scale speed motors.

According to the Atlas web site, the Lenz decoder (LE063XF) was factory installed in the C420 up to 2013 (not really "ancient" times). They began using NCE decoders (AN12A0) in 2013. If you're not really sure if yours are Lenz or NCE, read CV7 (Version Number). It will be 45 for the Lenz and 36 for the NCE. CV8, Manufacturer's ID will show 127 for both (= Atlas).

If they are in fact Lenz, I suggest you read and post CVs 2, 29, 67, and 94 to help us figure out what to do next.

If they are NCE decoders, the problem may be the torque compensation settings, CV116 and CV117. The factory default settings for both are 0, which results in a high start voltage. To get a lower start voltage and overall better slow speed control these need to be increased to 3-6 and 35-50, respectively.

But  -  if you're already on the way the replacing them with TCS decoders, I'll be happy to take the Lenz decoders off your hands!

[peteski]

According to the Atlas web site, the Lenz decoder (LE063XF) was factory installed in the C420 up to 2013 (not really "ancient" times). They began using NCE decoders (AN12A0) in 2013. If you're not really sure if yours are Lenz or NCE, read CV7 (Version Number). It will be 45 for the Lenz and 36 for the NCE. CV8, Manufacturer's ID will show 127 for both (= Atlas).

In the world of electronics, anything over few years old is ancient. 
You do have to admit that those Lenz decoders are fairly basic low-end decoders. While it is true than Atlas only stopped using them in 2013, the design of that decoders goes back several years before 2013.

Those are still perfectly usable decoders (and dare I say much better than the Bachmann basic decoders), but their design is dated.

[craigolio1]

Have you tried removing the decoder and running them in DC? Some times a half turn too much of a frame screw or something and it binds just enough to slow it down.

Craig