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Odd problem

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Odd problem
Posted by John-NYBW on Sunday, January 30, 2022 12:52 PM

About a dozen years ago I bought a P1K ABBA set of F3s. These are lettered for the Erie and numbered 714A/B/C/D with the A&D being the F3A units. I split the set up to make two AB sets. They haul my two coal trains, loads going east and empties going west. They both occupy dedicated staging tracks which are just long enough to hold the entire train.

For some strange reason, sometimes when I power up my DCC system, the 714A/B set lurches forward about a foot before stopping. To the best of my knowledge, the 714C/D set has never done that. The 714A/B is the only loco I have ever seen do this. This is more than a nuisance. Because its staging track is just long enough to hold the entire consist, when it lurches forward it blocks the rest of the staging yard ladder and if I haven't noticed that, it causes collisions and derailments with other trains trying to exit the staging ladder. 

Has anyone else had a similar problem and/or does anyone have any idea why it would do this and why it would only be limited to this one set of locos and only some of the time. I don't even have a good guess.  

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Posted by tstage on Sunday, January 30, 2022 1:02 PM

John,

What is the value of CV29 in your F3s?  My guess is that you have them set for dual-mode (DC & DCC) operation.  If they are, turn that off (i.e. subtract "4" from the value of CV29) and the lurching should stop.

My NCE Power Cab doesn't have DC capabitily so there is no need have it activated on my decoders.  My default for CV29 is "34" so that I can operate at 128 speed steps and addresses higher than 128.

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by MisterBeasley on Sunday, January 30, 2022 2:19 PM

On my staging tracks, each siding has a kill switch, just like each turntable track.  I know I shouldn't need kill switches with DCC, which I use exclusively, but it keeps the sounds off for idle trains and also turns off the interior lights in my passenger cars.

It takes an iron man to play with a toy iron horse. 

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Posted by Tophias on Sunday, January 30, 2022 7:53 PM

MisterBeasley

On my staging tracks, each siding has a kill switch, just like each turntable track.  I know I shouldn't need kill switches with DCC, which I use exclusively, but it keeps the sounds off for idle trains and also turns off the interior lights in my passenger cars.

Mr. B, I couldn't agree more. In 2011 I converted my layout from DC to DCC and Gerry Rooks said I didn't have to make any wiring changes. And he was correct. I had several DC blocks with toogle switches and made zero wiring changes. To this day, nothing has changed. Layout operates flawlessly. I believe that is due to the numerous feeders to the blocks. Point is, it was a blessing. I love sound locos, but with around 40 sound locos the noise would be deafening, even with my 70 year old ears 

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Posted by John-NYBW on Sunday, January 30, 2022 8:51 PM

I have kill switches to my roundhouse and staging yards where most of my idle locos are. The two coal trains have dedicated tracks that are electrically isolated from the rest of the staging tracks and don't have a kill switch. These locos are not sound locos so I had no reason to set up a kill switch.

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Posted by John-NYBW on Monday, January 31, 2022 12:45 PM

Lastspikemike

It might be interesting to place those particular locomotives onto a kill switch controlled siding and see if the same behaviour occurs when you turn the siding power on. If not then it's a power on phenomenon from your DCC powering up.

 

Not a bad idea but this only happens occasionally. Murphy's Law tells me that it's not going to happen when I'm trying to make it happen. I'm going to try tstage's suggestion regarding CV29. 

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Posted by John-NYBW on Tuesday, February 1, 2022 6:05 AM

tstage

John,

What is the value of CV29 in your F3s?  My guess is that you have them set for dual-mode (DC & DCC) operation.  If they are, turn that off (i.e. subtract "4" from the value of CV29) and the lurching should stop.

My NCE Power Cab doesn't have DC capabitily so there is no need have it activated on my decoders.  My default for CV29 is "34" so that I can operate at 128 speed steps and addresses higher than 128.

Tom

 

I checked the CV29 value for all four locos and it was 38 indicating analog mode was enabled. I changed it to 34. Since the problem only occurred sporadically, I won't know for a while if this was the root cause of the problem but it sounds feasible. 

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Posted by wrench567 on Tuesday, February 1, 2022 7:14 AM

Lurching and runaways would happen on our Lenz powered club layout on powerup. Usually on sections with a separate booster and sometimes on the section with the command station/ booster unit. The common factor was that all the locomotives involved had DC enabled in CV 29.

 Most of the club members did not have DCC at home so DC was enabled. It made some interesting times when something shorted and the boosters reset. There was one member who was dead set on DC. He would leave the command station and throttle on 00 all the time.

      Pete.

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Posted by richhotrain on Tuesday, February 1, 2022 7:36 AM

I run a DCC layout, and all of my locomotives are DCC decoder equipped. None of my decoders have DC enabled (bit 2). Never have, never will. It's just that simple.

I would venture to say that most of us who run in DCC only care about forward direction, 28/128 speed steps and long address. That is a total value of 34 in CV29. The other 4 bits can be safely ignored.

I will concede that there may be times when DC enabled is preferred such as running DCC locomotives on a DC club layout. In those situations, it is incumbent on the user to make the necessary change in the value of CV29 (by adding 4). Then change back the value of CV29 when getting back home.

As far as reverse direction is concerned, I only concern myself with that when running certain consists such as AA, ABA, ABBA. In my case, as an NCE user, I can do that automatically when setting up the consist.

Rich

Alton Junction

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Posted by John-NYBW on Tuesday, February 1, 2022 2:00 PM

wrench567

Lurching and runaways would happen on our Lenz powered club layout on powerup. Usually on sections with a separate booster and sometimes on the section with the command station/ booster unit. The common factor was that all the locomotives involved had DC enabled in CV 29.

 Most of the club members did not have DCC at home so DC was enabled. It made some interesting times when something shorted and the boosters reset. There was one member who was dead set on DC. He would leave the command station and throttle on 00 all the time.

      Pete.

 

That seems to fit because the lurching is occurring on a staging track that is in my second power district that has its own booster. Now that I have disabled analog mode, hopefully it will no longer be an issue. I had no idea it had even been enabled because the only change I made to the factory setting was to add a long address. When I discovered th default value was 38 for all these locos, I changed it to 34.

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Posted by John-NYBW on Tuesday, February 1, 2022 2:07 PM

richhotrain

I run a DCC layout, and all of my locomotives are DCC decoder equipped. None of my decoders have DC enabled (bit 2). Never have, never will. It's just that simple.

I would venture to say that most of us who run in DCC only care about forward direction, 28/128 speed steps and long address. That is a total value of 34 in CV29. The other 4 bits can be safely ignored.

 

I had one decoder which I installed in one of my C-linters which had a default value of 50 in CV29 which turns on bit 4. It has something to do with the Speed Curve and since I have no idea what a Speed Curve is, I left it as is. This was part of a AA set of C-Liners and since the other one would face the opposite direction, I gave it a CV29 value of 51. 

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Posted by John-NYBW on Tuesday, February 1, 2022 2:35 PM

Are there systems that require you to enter a hexadecimal value? Hexadecimal is a simple way to represent a binary number as 4 binary digits will equate to a single hexadecimal digit. 

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Posted by CSX Robert on Tuesday, February 1, 2022 5:11 PM

John-NYBW

Are there systems that require you to enter a hexadecimal value? Hexadecimal is a simple way to represent a binary number as 4 binary digits will equate to a single hexadecimal digit. 

 

As far as I know there are no current systems that require you to enter hexadecimal numbers.  Some of the early Digitrax systems with the DT100 and DT200 throttles did.  Those throttles were discontinued in 2000 and 1998, and the limitation was with the throttle, not the system, so even with the early systems you don't have to use hexadecimal with any throttle made after 2000 (DT300 or later).

If you want to, however, you can use hexadecimal with the DT300 - DT500 series throttles, I don't know about the DT600 series.

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