A problem shared is a problem solved?

[kitefighter]

Hello,

 

I recently had DCC Sound professionally installed on an Alan Gibson Black Five (also professionally built). Before the DCC Sound installation, the model ran fine. Since DCC Sound, the model seems stutters and cuts out. The following tests have been carried out.

 

1. The installation is of the new SWD chip by one of their recommended specialists. After fitting, the builder said that the model was rather light, and that contact is very important with DCC, so I should consider weighting the model, which is made of etched brass.

 

2. Following DCC Sound fitting, the model runs perfectly well if just in DCC without any sound.

 

3. Using any of the Sound features results in the model cutting out on running, and even stuttering whilst stationary.

 

4. The same track is used for other DCC models which run okay. However, the oval track has just one connection to the DCC power cab, so perhaps I need to look at the entie DCC set up.

 

Fitter has recommended I weight the model and have extra pickups fitted on the tender. Is this sort of problem typical for DCC Sound conversion on brass kit built models? Any other suggestions for resolving the issue?

 

[Nigelcliffe]

No, it is not typical.    Is this a 4mm or 7mm loco ?   I suspect with 7mm it may be the current output of a PowerCab.  But should not be an issue with 4mm. 

 

I've fitted quite a number of sound setups into kit built 4mm scale locos, many I suspect built to lower quality standard than your Black 5, and most much smaller than the Black 5.  All run immaculately when they leave me;  sound perfectly synchronised with movement, movement smooth and predictable, and no hiccups in sound output.  But, I often spend more than 5 hours fitting sound to a single loco, so any commercial installation is going to cost a fair bit in just time, let alone components.

 

 

Issues to look at:  

a)  pickup.   That is critical to any sound installation, slight drops in pickup may cause minute interruptions to the electrical current which then makes things poor running.  One area I would pay some attention to is the wheel treads; quite a lot of the wheels supplied to the kit market have, frankly, terrible wheel tread surfaces and need to be polished to remove those irregularities.  (Use a good magnifier, compare the tread quality of the kit wheel with a Bachmann or Hornby wheel).     
You imply pickups on loco only;  I'd expect to have pickups on all eight axles on each side (or at least six of them on both sides).  Only using three axles makes pickup a little less reliable, though should still be reasonable.  In future builds, tell your builder to fit pickups on all axles even if it will cost more money. 

 

b ) Loco mechanical properties.  Does the loco have any tight spots ?  This would be found by running on DC without a decoder, and with an analogue ammeter in series.  The ammeter will twitch slightly as the load rises and falls, those twitches will correspond with tight spots.   Those need solving before looking at decoders.

 

c)  Decoder tuning.   Has the decoder CV's been setup to match the model ?   If not, why not, does the fitter not know what he's doing ?  (If you've got to do it yourself, the CV54 auto-tuning method usually works well for a LokSound V4).

 

d)  Weight shouldn't be a big issue, though weight distribution is can be a serious issue.  If the loco's centre of gravity is towards the smokebox it may be unbalanced over the driving wheels.  More weight may help, but it needs to be in the "right" place, placing the load over the driving wheels. 

 

e)   It will benefit from a stay alive circuit, though it should run properly without one.  A Black 5 should have loads of room for a suitable circuit. I'd start by looking at 2000uF for stabilising the chip and particularly the sound playback.   An ESU module will provide much more run time, but it shouldn't be necessary to spend that much to solve the loco.   ESU manuals have details of where to solder the stay alive components to the side of the chip. 

 

 

 

- Nigel

[kitefighter]

Hello,

 

Thanks for your reply. In response to your questions. You sound very knowledgable.

 

 

No, it is not typical.   

 

That's reassuring. I've inherited a lot of kit built models that I'd like to get over to DCC Sound. All of them run well.

 

 

  Is this a 4mm or 7mm loco ?   I suspect with 7mm it may be the current output of a PowerCab.  But should not be an issue with 4mm. 

The loco is 4mm

 

 

I've fitted quite a number of sound setups into kit built 4mm scale locos, many I suspect built to lower quality standard than your Black 5, and most much smaller than the Black 5.  All run immaculately when they leave me;  sound perfectly synchronised with movement, movement smooth and predictable, and no hiccups in sound output.  But, I often spend more than 5 hours fitting sound to a single loco, so any commercial installation is going to cost a fair bit in just time, let alone components.

 

So you are a professional provide a service for customers? I'm sure your models are well made and to a high standard. The model I have is inherited from my late father, who was a fastidious collector. The model has an RG4 Portescap motor, which runs well, albeit a bit noisy. No problems prior to sending off to be fitted for  DCC Sound.

 

 

Issues to look at:  

 a)  pickup.   That is critical to any sound installation, slight drops in pickup may cause minute interruptions to the electrical current which then makes things poor running.  One area I > would pay some attention to is the wheel treads; quite a lot of the wheels supplied to the kit market have, frankly, terrible wheel > tread surfaces and need to be polished to remove  those irregularities.  (Use a good magnifier, compare the tread quality of the kit wheel with a Bachmann or Hornby wheel). 

 

I've had a good look as you suggest and compared it with a Golden Age Models A4. The driving are all clean, and have a brushed finish, where I assume there has been some wear through use. The bogie and tender wheels look dull and underused, not polished like the driving wheels but they are not pickup wheels.

 

   

You imply pickups on loco only;  I'd expect to have pickups on all eight axles on each side (or at least six of them on both sides).  Only using three axles makes pickup a little less reliable, though should still be reasonable.  In future builds, tell your builder to fit pickups on all axles even if it will cost more money. 

 

The model was built before DCC became popular, and has pickups on the four of the six driving wheels only, via thin metal bars, spring tensioned to hold contact with the inner rims. I suppose this worked well enough for analogue. I'll ask for the pickups to go to all driving wheels and the tender.

 

b ) Loco mechanical properties.  Does the loco have any tight spots ?  This would be found by running on DC without a decoder, and with an analogue ammeter in series.  The ammeter will twitch slightly as the load rises and falls, those twitches will correspond with tight spots.   Those need solving before looking at decoders.

 

I don't think the model has any tight spots, but it does seem to run better if I've run it for a good ten minutes when it was analogue. Because it has an RG4 motor, I can push it along a track and it moves with finger tip effort without any stiffness.

 

c)  Decoder tuning.   Has the decoder CV's been setup to match the model ?   If not, why not, does the fitter not know what he's doing ?  (If you've got to do it yourself, the CV54 auto-tuning method usually works well for a LokSound V4).

 

I have left this to the professional who installed it (not my builder and I don't think he builds models per se) recommended by SWD. I doubt the installation is at fault, since the function buttons all work and the model makes the correct chuff noises when it does run.

 

d)  Weight shouldn't be a big issue, though weight distribution is can be a serious issue.  If the loco's centre of gravity is towards the smokebox it may be unbalanced over the driving wheels.  More weight may help, but it needs to be in the "right" place, placing the load over the driving wheels. 

 

I found that when the model did stall, a light pressing down on the centre of the engine got the pickup back again. It has to be pickup because the model stops dead and so does the sound.

 

e)   It will benefit from a stay alive circuit, though it should run properly without one.  A Black 5 should have loads of room for a suitable circuit. I'd start by looking at 2000uF for stabilising the chip and particularly the sound playback.   An ESU module will provide much more run time, but it shouldn't be necessary to spend that much to solve the loco.  solder the stay alive components to the side of the chip. ESU manuals have details of where to - Nigel

Again, I've left this to the installation professional, who has advised that I carry try adding extra pickup connectors and add weight. I'll ask my builder to do this (though if as you suggest, DCC need more than just the four driving wheels to pickup, then perhaps he could have sorted this beforehand - trouble is, I think he's an electronics person, not a model railway builder) and will send it back to the fitter.

 

It has been a disappointing experience, but you live and learn I suppose.

 

Kind regards

 

 

[Nigelcliffe]

I do installations for people I know.  I don't run a commercial installation service, not least because sensible pay rates per hour would make the cost unreasonably high to most people.  

 

From what you have written, the fundamental issue is pickup.   Fit more pickups, and also add a stay-alive unit.  

 

I suggest seeking model makers and sound installers with experience of DCC in kit built locos.  There are often subtly different problems to those found in ready to run models. 

 

 

- Nigel

[Lady_Ava_Hay]

I have read the thread but am not sure if this is the case.

 

Is the loco using chassis return?

 

If so, this will cause stuttering as the axles are not sufficiently in contact with the bearings to transmit the DCC power ( and signal ) reliably.

 

I insisted on my US tank kit in having all insulated wheels and spring wire pick ups to four of the six drivers. A professional modeller helped me with that.

[Nigelcliffe]

A fair point David about pickup through bearings sometimes being a problem. However, it does usually work for split frame arrangements. If it is found to be a problem, then lightly sprung wire onto the axle is all that is needed; a well established method in 2mm finescale where split frame is the normal method and pickup problems are more common due to low weights.

 

Nigel

[darren01]

Hi 

My Friend had the same problem with his sound fitted 08, he in the end worked out that the sound chip was drawing far more current from his powercab was putting out, when the sound was off it ran fine, but once the sound was put on it was a pig.

It is to do with the powercab not putting out enough juice.

[newbryford]

Ok without sound, dodgy with sound on. Similar to a factory sound fitted Hornby 08.......

 

The decoder may be cutting out due to the extra current required when running with sound on. Lowering the volume setting often cures the 08. It may be worth trying that.

 

 

Cheers,

Mick

[kitefighter]

I have read the thread but am not sure if this is the case.

 

Is the loco using chassis return?

 

If so, this will cause stuttering as the axles are not sufficiently in contact with the bearings to transmit the DCC power ( and signal ) reliably.

 

I insisted on my US tank kit in having all insulated wheels and spring wire pick ups to four of the six drivers. A professional modeller helped me with that.

 

The loco is not carrying any current to the chassis. I made sure by checking before sending off the model. I will pack the model to my builder who unfortunately whilst not a DCC specialist, has fixed many models that have had poor pickup before. I'm still a little bit disappointed that the installation professional did not point out that four wheels pickup might not be sufficient but he says it ran fine on his test track and asked that I carry out my own additional work to get the additional pickups and weights before returning it to him.

 

I'm curious about fitting a "stay live" capacitor. If its a good idea, why isn't this standard practice?

[kitefighter]

I don't think it's because there is too much current being drawn. I test ran 4 locos on the same layout, all with DCC Sound switched on and no problems. I'm convinced, the problem is with the model and the pickup. The installer gave me an indication I may have a problem before returning it to me.

[Nigelcliffe]

Space should not be a problem for capacitor installation in 4mm scale.   Money, time and expertise might be a limiting factor.    I've got effective stay-alive capacitors inside a 2mm scale class 02 diesel shunter,  4 wheels and a loco which is 45mm long over the buffers.  The capacitors are in the cab side, in a space 4x8x8mm.  

 

Given this is "pay a professional" installation, then as well as dealing with pickup issues, decide between using a TCS KA1/KA2 unit or the ESU stay alive unit.   The ESU costs more (about £34), but in a better position to argue over any warranty issues. The TCS may need a few extra components before attaching to a LokSound - my use of TCS KA units has been onto Zimo sound chips.   As there is a tender, as Dutch Master indicates, that's loads of space for both capacitor units and a large speaker enclosure.  

[kitefighter]

Space should not be a problem for capacitor installation in 4mm scale.   Money, time and expertise might be a limiting factor.    I've got effective stay-alive capacitors inside a 2mm scale class 02 diesel shunter,  4 wheels and a loco which is 45mm long over the buffers.  The capacitors are in the cab side, in a space 4x8x8mm.  

 

Given this is "pay a professional" installation, then as well as dealing with pickup issues, decide between using a TCS KA1/KA2 unit or the ESU stay alive unit.   The ESU costs more (about £34), but in a better position to argue over any warranty issues. The TCS may need a few extra components before attaching to a LokSound - my use of TCS KA units has been onto Zimo sound chips.   As there is a tender, as Dutch Master indicates, that's loads of space for both capacitor units and a large speaker enclosure. 

 

 

Thanks for the advice. I will definitely consider fitting a stay live capacitor, but only after increasing the number of wheels that are live for pickup, to establish is this makes a difference. I've asked the builder to add weight to the model as it is one of the lightest in my fleet.