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Readjusting decoder direction


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Hello Guys

 

Yesterday, I purchased a Realtrack Class 156, and added a Bachmann 21 pin decoder into each car.

Both cars are moving in opposite directions, so of course I need to alter the direction of one.

I’m not great at this sort of thing, and I don’t want to be messing around with CV’s until I understand what I’m doing for fear of messing up the chip setting.

My controller is a Gaugemaster Prodigy 2.

I have read through the booklet, but that’s just confused me more

 

I am aware that this subject may have been covered previously, but could anyone give me an idiot guide of how to alter this specific to the chip / controller I am using please ?

 

Thank You

John

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Read the value of CV 29 on the one you want to change the direction of and add 1 if the value you read is EVEN, if the value you read is ODD then subtract 1

 

This will change the direction to be the same as the other one

 

Or you could swap the wires on the motor left for right, first method is easier though :)

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Cheers Iain

 

I’m not good with this subject.

How do you reprogramme the CV29 value please ?

 

I’ve read the values on each chip

One reads 006, the other 021

Odd and even as you have stated, so I need to change one of them to either 022, 0r 005, yes ?

 

Cheers again

John

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  • 6+1=7 or
  • 21-1 = 20

 

write either 7 or 20 to the appropriate loco, but only change one loco.

 

Though I don't understand why with 2 locos on the same train they have such a difference.

 

the one with 20 had the reverse direction selected, that is what we are taking off but it also has a complex speed curve set which doesn't make sense if the other end doesn't also have a complex curve set.

 

but if changing one of the CVs as suggested above sort out the issue that is what you want to do :)

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  • RMweb Gold

Though I don't understand why with 2 locos on the same train they have such a difference.

The OP said that they added Bachmann decoders themselves. Had the decoders been previously used elsewhere? If not, yes, it is a puzzlement.

 

If they have already been used elsewhere a full reset might be an idea then start the outlined process from scratch.

Edited by BoD
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Thanks for the info guys.

 

Sorry, I should have stated that the decoders have been previously used in other loco's.

These are spares now hence why I've used them

 

This will also explain why they have two different values allocated within CV 29 I'm assuming

 

I will be calling Gaugemaster today to ask their advice on changing one of these decoders as for some reason the handset won't allow me to do so.

I have no doubt, it's something daft I'm not doing, it will be a simple fix I'm sure, but i will keep the subject informed.

 

I managed to do it once through fluking it somehow, but the lights would only work on the even numbers when throttle was applied on the handset

On the odd numbers it went off.

 

Cheers

John

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If they have been used then the first action should be to reset them back to defaults to ensure that they are both the same across all CV values.

 

Write CV8=8 and then change the address in CV1 to the number you want the train to have

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If you’re trying to reset the one in the dummy car it probably won’t work - you need a motor load across the decoder to reprogram it. Either change CV29 in the motor car, or put the decoder into a motorised unit to program it.

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If you’re trying to reset the one in the dummy car it probably won’t work - you need a motor load across the decoder to reprogram it. Either change CV29 in the motor car, or put the decoder into a motorised unit to program it.

If it wasn't motorised it wouldn't be trying to move in the opposite direction.

 

 

Both cars are moving in opposite directions, so of course I need to alter the direction of one.

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  • RMweb Gold

If it wasn't motorised it wouldn't be trying to move in the opposite direction.

 

 

 

It may not be moving in the opposite direction but the head/tail lights may be suggesting that it it were moving  then it looks as though it may be moving the wrong way round. That is unless the Class 156 has motors in both vehicles.

 

I've usually put both DMU cars on the (programming) track, set CV 29 the way I want it for the trailer car and then remove the trailer car and change/reset CV 29 (again) on the motor car.

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..

...

Both cars are moving in opposite directions, so of course I need to alter the direction of one.
...

Thank You
John

 

 

It may not be moving in the opposite direction but the head/tail lights may be suggesting that it it were moving  then it looks as though it may be moving the wrong way round. That is unless the Class 156 has motors in both vehicles.

 

...

 

seems fairly clear to me in the OP - have highlighted it to help :)

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  • RMweb Gold

I suggest giving both decoders a factory reset. Then see how the train behaves. The CV values cited above (post) imply the wiring in the train is expecting both decoders to have the same direction set up in CV29. If the train is now moving but the "wrong way" it may be easiest to take it off the track and turn it round. Then you may not need to look at CV29 at all.

 

When the train is moving in the desired direction you can change the decoder addresses from 3 to whatever is whatever is wanted.

 

- Richard.

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The Realtack Class 156 units do have separate bogie mounted motors in each car, so they can drive independently (and in the opposite direction).  Mine arrived DCC Sound fitted, so they were set up for me by Charlie, but the 'train crew manual' that came with mine indicates that the CV29 values should be set at 7 and 14.  However, I notice that this is on a sticker that was added to the front of the information booklet, possibly only on the ones pre-fitted with DCC chips by DC kits.  I'm not sure why the recommendation is to have one car Railcom enabled and the other not, but since I don't as yet use Railcom, it doesn't matter.  Of course, these are by default set up for a short address (ie 3), so if you programme a long address, these values will change anyway.  The key point is that one of the two cars needs to have an even number and the other an odd number.  Personally, I'd probably go for 6 and 7 if you are not using Railcom, which means you only have one to change.

 

Although having noted that you have this problem when one is even and the other odd, I'dd probably go with 6 in both vehicles until you are ready to make further CV changes.

 

Edited to add the last sentence.

Edited by Dungrange
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The reason you only want railcom on one decoder is that some automation programmes have a challenge when receiving a Railcom ID from more than one loco with the same address, especially when they are both in the same block :) Even if you give them different addresses some programmes cant handle 2 Railcom addresses in one block - luckily mine can :)

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Ok guys, this is what’s happened today.

 

I called Gaugemaster this morning, and a very nice chap told me to leave the chip set on CV29 to 006 alone, and alter the other chip, which had a CV29 value to 021 also to 006.

I was wary of this due to what you guys have said above, but he said this would clear the issue.

 

We all know that this wasn’t the case, therefore back to square one !

 

I called them again, and they were less than helpful , I think this was due to the fact I was asking about Bachmann chips and not their own, but they did tell me to change one to a CV29 number 005.

Other than that they didn’t know. Marvellous !

 

I changed it to 005 and the two cars did run in the same direction, but when adjusting the running speed on the controller, the tail / headlights on this car lit when the controller speed was on an even number, but went off on an odd number.

 

Decided to have a crack at changing it to 007, and bingo, I got there, running and lights ok

 

This is all due to the advice given by you all above to which I am most greatful, Thanks

 

You learn something new every day in this hobby !!

 

John

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  • RMweb Gold

On mine the front car has CV29 set at 2 and the rear set to 3. (DC running disabled) Works perfectly. If you want DC running you probably want to set CV29 to 6 and 7.

 

Do note the recommendation with the 156 is to program each car separately but to the same address.

 

 

CV29 set to 5 disables 28/128 speed steps which I'm pretty sure the lights on the 156 won't be a fan of.

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Iain,

 

I have setting 06 at one end, 07 at the other. Works fine. Simple when you know how, but this is the first unit where I have had to install 2 decoders, hence why I've never had to go in to this setting.

 

Just a quick question whilst we're on this subject, the two headlights both come on simultaneously.

I have another Railtrack 156 that was fitted with sound from purchase where both headlights plus the small rectangular light on the non drivers side work.

 

I can't make my mind up whether this is incorrect, or whether this was adapted when the actual units were refurbished

When refurbished into Saltire livery, the 156's were fitted with LED headlights

 

The sound fitted unit in question is 156494 in Scotrail Saltire livery

Non sound is 156453 in Scotrail Barbie livery

 

 

As the Barbie one runs perfectly now, I'm again wondering if this lighting is correct for the model, or whether the sound chips fitted to my other unit enable this rectangular light to work ?

 

Has anyone else got a Barbie liveried one and can inform me if this is correct please ?

 

John

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My worry would be that as you didn’t reset both decoders that you have lost of other values that are different and that there is potential for the motors to be fighting each other due to different parameters being set such as accel/decel, start speed, max speed etc.

 

The fact that one had CV29 set to 21 suggests that at least that chip had been played with.

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I don't think anyone has mentioned this http://www.2mm.org.uk/articles/cv29%20calculator.htm yet.

 

A value of 6 is DC on, 28/128 step enabled.

 

The value of 5 (and also 21) tells the decoder to interpret speed commands as 14 step and take the light control from a bit in the speed value. That's why the lights change with odd/even speed steps.

 

The value of 21 is to use the speed table rather than just the basic speed CVs.

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Read the value of CV 29 on the one you want to change the direction of and add 1 if the value you read is EVEN, if the value you read is ODD then subtract 1

 

Kudos for this, rather than just telling people to add/subtract without knowing the starting value, which can be a disaster.

 

For example, if CV29 = 7 (Railcom off, DC on, 28/128 speed steps, reverse) and you ask how to change the loco direction, all too often I have seen the reply "add 1 to the value in CV29" (or 2 or 4 for changing other bits). If you do this, you end up with CV29=8 (Railcom on, DC off, 14 step, forward) which is almost certainly not what you wanted.

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  • 1 year later...
On ‎09‎/‎12‎/‎2018 at 18:45, WIMorrison said:

Read the value of CV 29 on the one you want to change the direction of and add 1 if the value you read is EVEN, if the value you read is ODD then subtract 1

 

This will change the direction to be the same as the other one

 

Or you could swap the wires on the motor left for right, first method is easier though :)

Excellent, thanks for this.  I had cocked up and got them running the same way, but this sorted it perfectly... :D

 

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On 11/12/2018 at 14:24, Crosland said:

I don't think anyone has mentioned this http://www.2mm.org.uk/articles/cv29%20calculator.htm yet.

 

A value of 6 is DC on, 28/128 step enabled.

 

The value of 5 (and also 21) tells the decoder to interpret speed commands as 14 step and take the light control from a bit in the speed value. That's why the lights change with odd/even speed steps.

 

The value of 21 is to use the speed table rather than just the basic speed CVs.

This a great little tool - thanks 2mm Assosiation. If you never intend to run the model on a dc layout turn dc off in cv29 and you'll almost guarantee to improve running.

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