Locomotive Performance

[JOHN VAN]

Hello,

Years ago I purchased a Kato HO scale NW2 switcher.  Recently, I converted the locomotive over to dcc and installed a Digitrax decoder.

For the most part, the locomotive runs great.  However, at the slowest of speeds it displays a horizontal jerking or shaking motion when moving forward.  In reverse, the problem is non-existent.

I recently cleaned the wheels and contacts, but it didn't help.  Anyone have any ideas on how to fix this?

Thanks

 

[rrinker]

 WHich decoder did you install? You may need to tweak the motor control CVs for best low speed performance.

                    --Randy

 

[JOHN VAN]

Thanks Randy.  It's a Digitrax DN136D

[tstage]

I have a Z-scale Digitrax decoder in a Proto 2000 S1 switcher.  It has good motor control but at slow speed it is a little jerky and somewhat noisy.

For future installs I would opt for a TCS decoder.  The have excellent motor control, crawl unbelievably well, and are quiet.

Tom

[mbinsewi]

Just an idea, take the shell off, and watch the drive line and worm gears as it runs, back and forth, at the slow speed.  You might need a thrust washer at the worm gear.

Worth a check, before you get into motor control.

Mike.

[mobilman44]

I tend to agree with Mike.  Sounds like a mechanical problem more than an electronic one - or not.   Anyway, its easier to check out the gears and shafts before hitting the decoder.............

[Guy Papillon]

Did you run that loco on DC before installing the decoder? If so, you should know if it ran OK before. Then you know if the problem is with the decoder or a mechanical flaw on the loco.

Personally, I once bought a low end Digitrax decoder for a Bachmann steam loco. Whatever I tried, I was unable to make it control the loco as I would have liked. Forward slow speed control is unpredictable and in comparison with backward, it needs about three speed steps more to start the loco. Someone on this forum told me that the problem is with the lack of BEMF on this particular decoder. Needless to say that I had never bought such a decoder again. For basic decoder installation, I now rely on TCS T1.