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TCS WOW -Athearn Genesis F9 runs jerky at slower speeds

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  • Member since
    January 2014
  • From: Moneta, VA USA
  • 1,175 posts
TCS WOW -Athearn Genesis F9 runs jerky at slower speeds
Posted by gdelmoro on Friday, September 15, 2017 9:37 AM

Hi all, I have an Athearn Genesis F9 that I installed a TCS-WOW w/KA kit into. The connections were Trucks, Motor, Speaker and Front & Rear lights.  Every thing works. 

Unfortunately the loco does not run smooth at slower speeds.  It Jerks and does not smooth out until about speed step 8 using 28 speed steps.

Any advice?

Gary

  • Member since
    June 2004
  • From: From Golden, CO living in Puyallup (Seattle), WA
  • 751 posts
Posted by Renegade1c on Friday, September 15, 2017 12:57 PM

This has to do with BEMF. It needs adjustment. I had the same thing happen to me on two switchers. Personally I just disabled it and messed with the speed curves to get what I needed but to each their own.

I have seen this happend with more than just my two TCS decoders and I'm not sure what the solution is. Loksound's also do it but have an auto adjust feature on them to correct it. 


Colorado Front Range Railroad: 
http://www.coloradofrontrangerr.com/

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  • Member since
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  • From: Moneta, VA USA
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Posted by gdelmoro on Friday, September 15, 2017 3:17 PM

If I disable BEMF does that mean the loco won't maintain speed up grades without me manually adding throttle?

Gary

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Friday, September 15, 2017 3:50 PM

 TCS BEMF is also self-adjusting, there's just not special process, it just adjusts as you run the loco. All mine run great, but they are all either P2K or Bowser/Stewart locos. They sometimes are a little rough for the first few feet, then they settle down, I've never turned the BEMF off on my TCS decoders.

 Run it for a while, in each direction, it should settle down. Or there is a mechanical bind.

 My Loksounds, I haven't ever run the BEMF adjust, although I might after atchign another video with it demonstrated. My locos run great at slow speed without ever adjusting anything, but the adjustment may make them even better.

                           --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Stevert on Friday, September 15, 2017 6:03 PM

Gary,

I had a TCS Wow installed by TCS in a Kato SD40-2 at Train Fest last year.  Got it home and had the same issue - jerky up until maybe speed step 10 or 12. 

Doing the "Sound-Assist" BEMF adjustments outlined in their manual just made it worse.  In addition to it running jerkily, the prime mover would now rev up to notch 8, drop back to idle, rev back up, etc.  Neither re-doing the Sound Assist BEMF adjustments, or doing manual BEMF adjustments helped.

What I ended up doing was using the Sound-Assist menu to select Traditional Throttle Mode, then I manually turned off BEMF by subtracting 1 from the value in CV61.

It runs MUCH better after having done that. 

  • Member since
    January 2014
  • From: Moneta, VA USA
  • 1,175 posts
Posted by gdelmoro on Saturday, September 16, 2017 6:27 AM

Stevert

Gary,

I had a TCS Wow installed by TCS in a Kato SD40-2 at Train Fest last year.  Got it home and had the same issue - jerky up until maybe speed step 10 or 12. 

Doing the "Sound-Assist" BEMF adjustments outlined in their manual just made it worse.  In addition to it running jerkily, the prime mover would now rev up to notch 8, drop back to idle, rev back up, etc.  Neither re-doing the Sound Assist BEMF adjustments, or doing manual BEMF adjustments helped.

What I ended up doing was using the Sound-Assist menu to select Traditional Throttle Mode, then I manually turned off BEMF by subtracting 1 from the value in CV61.

It runs MUCH better after having done that. 

 

Think I'll start with what randy suggests and if it doesn't work I'll try this.

Thanks

Gary

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, September 16, 2017 12:08 PM

 I'd be very disappointed if TCS wrecked their very nice BEMF. All my motor-only TCS locos run nice and smooth at all speeds, with excellent slow speed. And I never had to fiddle with them. I know Jeff Otto, who has that huge awesome Missabe Road layout totally disagrees with me and things TCS decoders have horrible drive, and prefes Digitrax. But every Digitrax one I've had has a horrible jump every few speed steps fromt he accumulating error in the BEMF algorithm (since computers work in binary, when you make calculations based on decimal numbers, not every result can be exactly represented in binary, so some rounding needs to occur. It appears that Digitrax 'accumulates' this error until it is enough to make the next calculation say jump up by 3, as opposed to the round off that made each prior calculation jump by 1). You can fiddle with the settings and reduce the effect but even after a whole bunch of tuning it's still noticeable. That's why relatively early on I switched to TCS.

                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    December 2001
  • 1,932 posts
Posted by Stevert on Saturday, September 16, 2017 7:10 PM

rrinker

 I'd be very disappointed if TCS wrecked their very nice BEMF. All my motor-only TCS locos run nice and smooth at all speeds, with excellent slow speed.

I have a few TCS non-sound decoders, too, and yes they run fine at all speeds.  Didn't have to tweak the BEMF at all, in any of them. 

And the WOW in Prototype Mode with BEMF turned on runs okay once you get up to or past the speed step 12-15 range.

But slow speed with that stuff turned on is just awful.  Unless that gets fixed somehow (firmware upgrade?), I won't buy any more.

  • Member since
    January 2014
  • From: Moneta, VA USA
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Posted by gdelmoro on Tuesday, September 19, 2017 12:56 PM

I ran the loco forward and reverse for 1/2 hour each. I took the shell off to see if there was anything obstructing the mechanism and lubricated the motor.  It seems better but when pulling 8 - 10 cars the jerking is very obvious still. Tongue Tied

Gary

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