Arnold/Hornby SW 1 DCC Troubleshooting

[jpwisc]

Rookie mistake, I forgot to test the SW1s I got before I detailed and painted one of them. They both run horribly. In DC (using 00 on a Zephyr) they go about 2 inches, stall then go again. With a TCS decoder I get lights but no motor control. I took one apart, cleaned it and checked everything out with no improvement.

They both run fine when I use a 9v battery on the rails like PowerSteamGuy did. I'll go fight them some more now...

Update: With the decoder in it accepts programming. I changed the address and now when I have it on the layout both front and rear lights come on. As I turn the throttle up, the wrong direction light dims down. Turn the throttle down, the light comes back up. Bizarre. Still no movement.

[peteski]

Rookie mistake, I forgot to test the SW1s I got before I detailed and painted one of them. They both run horribly. In DC (using 00 on a Zephyr) they go about 2 inches, stall then go again. With a TCS decoder I get lights but no motor control. I took one apart, cleaned it and checked everything out with no improvement.

They both run fine when I use a 9v battery on the rails like PowerSteamGuy did. I'll go fight them some more now...

Update: With the decoder in it accepts programming. I changed the address and now when I have it on the layout both front and rear lights come on. As I turn the throttle up, the wrong direction light dims down. Turn the throttle down, the light comes back up. Bizarre. Still no movement.

You most likely have the decoder installed upside down. See the SW-1 tech review (I pointed to earlier in this thread) for details.

As far as running it on DCC address 0, I do not recommend that. This loco uses a coreless motor and the DCC analog "zero-stretching" signal does not get along with coreless motors (and can burn them up).

[jpwisc]

You most likely have the decoder installed upside down. See the SW-1 tech review (I pointed to earlier in this thread) for details.
...

Your tech review was awesome, it was part of the reason I decided to pull the trigger on these engines.

I did have the decoder in upside down at first. I flipped it and now I get the bizarre light behavior, but still no motor.

[peteski]

Your tech review was awesome, it was part of the reason I decided to pull the trigger on these engines.

I did have the decoder in upside down at first. I flipped it and now I get the bizarre light behavior, but still no motor.

OK, then I I'll say you now have the decoder in upside down.  The pinout they used on these decoders could have been done in a way that it deals better with upside down installs.

While the track power pins are in the center (pin 3 and 4) which will work when installed in either direction then the outside pairs of pins are headlights on one side and motor on the other.  if you plug the decoder in upside down. it will usually still take programming. But the motor leads are now supplying power to the headlights and the function outputs are trying to power the motor.

Since the function outputs can only supply "ground" when they are turned on (they cannot supply positive voltage) the motor will not run. But the motor outputs feeding the headlight circuit will manage to illuminate the headlights (since the motor drive is capable of supplying "ground" and positive voltage).  That combined with the fact that the internal loco circuit is providing the positive voltage to the LEDs (the blue wire output missing from the 6-pin decoders), will result in some strange behaviors.

The other possibility is that the RFI suppression components in the motor circuit are affecting the decoder's motor control.  They didn't affect a Digitrax DZ125, but could be affecting the TCS decoder. Do you have any way to test the decoder? Either on the bench or in another locomotive with a 6-pin socket?  That would be a good thing to try.

We should really take this troubleshooting to the DCC section of the forum (so it is easier to find when someone looks for this type information in the future).  Maybe the moderators could take these few posts and split this thread?

Calling @John  @Ed Kapuscinski  @tom mann @Dave Vollmer

[jpwisc]

I pulled the decoder and installed in in a FVM ES44. I checked in on the programming track and reprogrammed the new address. It ran smooth as could be.

I re-installed the decoder in the SW1 (making sure pin 1 was in the pin 1 hole) and it ran! It's not the smoothest, but I'll give it some break-in time and see what happens.

Thanks for the info on the coreless and 00 running. That would explain the bizarre behavior from the command station.

[peteski]

I pulled the decoder and installed in in a FVM ES44. I checked in on the programming track and reprogrammed the new address. It ran smooth as could be.

I re-installed the decoder in the SW1 (making sure pin 1 was in the pin 1 hole) and it ran! It's not the smoothest, but I'll give it some break-in time and see what happens.

Thanks for the info on the coreless and 00 running. That would explain the bizarre behavior from the command station.

Digitrax, TCS (and several other brands of) decoders do not control coreless motors well. Then the RFI suppression in the motor circuit often makes things even worse.

If you bought and installed a ZIMO or ESU decoder you would be amazed with the difference in the motor control.

[wazzou]

Pete, I'm confused by your contradiction in the statements about TCS decoders.
Are they bad for coreless motors or good?

[peteski]

Pete, I'm confused by your contradiction in the statements about TCS decoders.
Are they bad for coreless motors or good?

Fixed (I hope). 

[mu26aeh]

So which models have coreless motors ?  How do you tell the difference ?

[peteski]

So which models have coreless motors ?  How do you tell the difference ?

Unless it is mentioned in the model's features, or you take the model apart and examine the motor there is no easy or sure way to tell.  It seems that more and more N scale models are equipped with the inexpensive  coreless motors. In the past coreless motors were precision-made in Switzerland or Germany, and were very expensive. They often featured exotic features such as precious-metal commutators (for long life).

But with the proliferation of inexpensive flying models (quad-copters and similar) low-grade coreless motors are now widely available from Chinese manufacturers.  So model train manufacturers seem to have utilizing that type of motor in the new models.   Coreless motors are usually have smaller physical size and are lighter than a standard electric motor of equivalent power or torque.

[jpwisc]

Fixed (I hope). 

It still says TCS is bad and good. I'll order a Zimo and see how it does.

[peteski]

It still says TCS is bad and good. I'll order a Zimo and see how it does.

  - I totally missed that - fixed it now. Too many TLAs in our lives. 

Best prices and availability I found for ZIMO and TCS decoders is at http://sbs4dcc.com/ . Great customer service too.

[ryan_wilkerson]

I second this. I haven't found many USA sellers of Zimo but luckily I haven't needed to. Streamlined Backshop has the best prices and always had inventory when I needed it.
This is the one I use for FVM locos (GEVO, GP60, GP60M and now the SW1): http://store.sbs4dcc.com/ZIMOMX622NMicroDCCDecoder-NEM6516-pinIntegralConnector.aspx
He's running a free shipping sale for orders over $150 until Dec 31.

Best prices and availability I found for ZIMO and TCS decoders is at http://sbs4dcc.com/ . Great customer service too.

[jpwisc]

Update! My Zimo decoder arrived, installation was the normal 6 pin breeze (figuring which side up was tougher, all the instructions were in German).

What a difference! The SW1 ran like a dream! The Zimo is definitely the way to go for these. Thanks for the help Peteski!

[peteski]

I'm glad you're happy with it Karl!  Yes, the difference in motor control between Zimo and the American-made decoder is amazing (especially with coreless motors).  While the instructions in the little plastic box are in German, you can download the English version of the full decoder manual from Zimo.

http://www.zimo.at/web2010/documents/MX-KleineDecoder_E.pdf

As far as the 6-pin decoders go, pin 1 is usually marked somewhere on the circuit board.  The good thing is that even if you plug it in upside down, you will not damage anything - it will just act strange.  I wish that they laid the pins out differently in this setup: they could have arranged the signals on the 6-pin connector in such a way that it would work, even when plugged in upside down (the loco run backwards).  But the standard is already defined and that won't happen.