Should they stay, or should they go?

[Dieseldog]

Just running in a Bachmann class 03, I think I read somewhere that it was advised that after running in and fitting the chip that these little yellow (sorry don't know what they are called) things should be taken off, is this something that fellow members do or not? I don't know the reason behind this,

I hope you can shed a little light, thanks

[Dieseldog]

Sorry file too big I will upload a smaller pic

[TheWeatheringMan]

Just running in a Bachmann class 03, I think I read somewhere that it was advised that after running in and fitting the chip that these little yellow (sorry don't know what they are called) things should be taken off, is this something that fellow members do or not? I don't know the reason behind this,

I hope you can shed a little light, thanks

Hi,

It is normally reccomended to remove the tv supression capacitors fitted to locos after a dcc decoder is fitted.

This is because capacitors can often interfere with the dcc signal and cause various running problems.

The decoder has more effective supression built in to it than the separate capacitors fitted to the chassis.

Many dcc equipment manufacturers advise this as a policy to avoid these potential problems but the silly thing is that the train manufacturers such as Hornby and Bachmann cannot give this advice due to legal requirements upon them as manufacturers.

It is not illegal for you to remove the capacitors from your locos due to those present within the decoder - these being part of the decoder circuit they do not cause the potential running problems.

 

I've worked in DCC for over ten years and have always removed chassis capacitors.

One of the most telling instances that illustrate this was a Bachmann GWR 56xx tank fitted with a Bachmann decoder. As is its running was very poor and eradic on my Digitrax controller. once the capacitors were removed from the motor all was perfect.

Most Hornby locos run better with the capacitors removed.

My advice would be to remove said capacitors - however you must make sure you are removing the capacitors and not the shunts (these look like two small coils of wire) that assist with slow running.

If you can upload a picture i'll do my best to advise you when I can see the chassis layout - I have two of the newer Bachmann 03's but they are still boxed at the moment and buried in my store and difficult to get at at the moment.

Hope that helps.

Regards

[Dieseldog]

Thanks for the reply, just out of curiosity what do they actually do, might be a dumb question but if you don't ask you know!

[TheWeatheringMan]

Thanks for the reply, just out of curiosity what do they actually do, might be a dumb question but if you don't ask you know!

Hi,

Not a dumb question at all - asking is how we learn of course.

If you mean the capacitors : when the brushes in the motor run against the comutator to supply electricity to the windings and make the motor turn they pass over gaps or slots between the comutator sections. In doing so they can cause tiny sparks - this is perfectly normal.

These sparks radiate what is effectively a radio signal and it is this that can cause interference on radio and tv reception. The capacitors basically 'damp out' or absorb these radiated signals.

 

If you mean the 'shunts' : these are effectively coils of wire that add resistance to the circuit and assist in improving the slow running of the motor. This is mainly aimed at DC analogue running but the shunts dont cause a problem in DCC running and can be left in circuit. The settings available in the DCC decoder offer a far more comprehensive control over the running characteristics such as slow running.

 

Hope that makes it understandable and hasnt 'baffelled you with science' !!.

Regards

[buffalo]

Welcome to RMweb! This is a question that arises very often on here, so a search will find you many topics that will provide a range of opinions as well as much nonsense. Yes, it is safe to remove the capacitors and running will often improve as a result. The effect may vary with different decoders as does the effective suppression provided by the decoder. The supression was more or less essential with DC and old 405 and 625 line TVs but is rarely a problem with modern digital sets. Similarly FM radio is rarely affected, but other bands can be. In particular if one of your neighbours is a radio amateur, removing capacitors on DC will not endear you to them.

 

...If you mean the 'shunts' : these are effectively coils of wire that add resistance to the circuit and assist in improving the slow running of the motor. This is mainly aimed at DC analogue running but the shunts dont cause a problem in DCC running and can be left in circuit.

 

No, the shunts or, more usually, inductors have near zero resistance at DC and the resistance increases as frequency increases. They therefore provide a resistance to the high frequency signals produced by sparking, etc. Again, they can potentially cause problems with DC controllers that use modulated DC and with BEMF control on DCC. They can also be removed but should be replaced with simple wire links. It is also worth noting that not all inductors look like wire coils. Some look just like resistors to the uninitiated. The way to be certain is if they are in series with the motor (i.e. in line between a pickup and a motor terminal, not bridging the two motor wires or terminals) then they are inductors, whatever you think they look like.

 

Nick

[Dieseldog]

I have removed the yellow capacitors and I am left with two inductors/shunts? These are either side of the motor and are in series i.e between the pick ups and the motor.

Should these be removed as well? What difference will or should see by doing so?

Thank you again for the knowledge (I'm getting interested now)

[buffalo]

It won't do any harm to replace them with plain wire links. Whether or not you see any effect is another matter entirely, probably highly dependent on the individual decoder and motor. Others can say what effect they have seen but your experience may differ. You're at the point where expeimentation begins.

 

Nick

[Dieseldog]

Well firstly thank you very much for the advice on the capacitors, secondly I haven't yet removed the inductors.

I have however fitted a different chip and the difference is unbelievable, the original chip was a Bachmann one supplied with the loco, I've swapped this for a lenz silver mini and all I can say "it's magic".

I runs really superior to what it did and can shunt at a incredible slow speed, it's took 2 1/2 mins to complete a section of Hornby R601 straight track, I'm fascinated.

Next job is to run my class 08 in!

Thanks to all who contributed.

[JJGraphics]

It won't do any harm to replace them with plain wire links. Whether or not you see any effect is another matter entirely, probably highly dependent on the individual decoder and motor. Others can say what effect they have seen but your experience may differ. You're at the point where expeimentation begins.

 

Nick

 

Completely agree with buffalo.

 

I've been messing with DCC for about six years now and after early experiences of various issues with poor running of both

Hornby and Bachmann locos when the factory-installed components were initially left in place, I now remove all of these as

a matter of routine.

 

The improvement in running in some cases was not far short of miraculous, whilst in the case of locomotives that ran reasonably

well in the first place, the removal of the components made little or no noticeable difference. However a little tweaking of some

of the CVs did cure any remaining running issues.

 

As I mentioned in another post, a friendly neighbour is a very experienced TV engineer and amateur radio enthusiast and

carried out tests for RF interference. None of my locomotives which have had the factory-installed components removed

and a (Loksound V4) decoder fitted emit any measurable RF signals, however out of the box some locomotives did . . .

[AMJ]

I often tweak the acceleration and deceleration values as they can also make a big difference to the running quality.

[Adrian Wintle]

 

As I mentioned in another post, a friendly neighbour is a very experienced TV engineer and amateur radio enthusiast and

carried out tests for RF interference. None of my locomotives which have had the factory-installed components removed

and a (Loksound V4) decoder fitted emit any measurable RF signals, however out of the box some locomotives did . . .

 

I never quite understood why all the UK locos had capacitors etc., and yet contemporary North American locos (look at an Athearn blue-box loco) had no suppression components. Is it that the standard UK house wiring is a better antenna than standard NA house wiring?

 

Adrian

[Crosland]

I never quite understood why all the UK locos had capacitors etc., and yet contemporary North American locos (look at an Athearn blue-box loco) had no suppression components. Is it that the standard UK house wiring is a better antenna than standard NA house wiring?

 

Adrian

 

A number fo possibilitoes in decreasing order of lieklihood:

 

Differing national requirements. The EU EMC regulations are more stringent than the US FCC rules.

 

The US locos do not produce so much interference.

 

The US manufacturers (and maybe european importers) are ignoring the law.

 

It's nothing to do with house wiring. Without suppression, the RF noise can be radiated by the track and picked up by TV and radio aerials.

 

Andrew

[markw]

I never quite understood why all the UK locos had capacitors etc., and yet contemporary North American locos (look at an Athearn blue-box loco) had no suppression components. Is it that the standard UK house wiring is a better antenna than standard NA house wiring?

 

Adrian

UK housing is on average much smaller and closer together than in the US, so the noise doesn't need to travel as far in the UK to affect other peoples equipment.

[Adrian Wintle]

UK housing is on average much smaller and closer together than in the US, so the noise doesn't need to travel as far in the UK to affect other peoples equipment.

 

But running model railway equipment in an appartment (flat) would still be a problem then, wouldn't it?

[Adrian Wintle]

A number fo possibilitoes in decreasing order of lieklihood:

 

Differing national requirements. The EU EMC regulations are more stringent than the US FCC rules.

 

The US locos do not produce so much interference.

 

The US manufacturers (and maybe european importers) are ignoring the law.

 

It's nothing to do with house wiring. Without suppression, the RF noise can be radiated by the track and picked up by TV and radio aerials.

 

Andrew

 

I'm sure the reason there is a difference is more stringent regulations, but I don't understand why there would be a difference that would require them.

 

I don't believe I have ever seen model railway equipment causing interference on TV or radio, even in the same house (hairdryers definitely did). We've been running various stuff, including old Tyco and the like with resistance mat controllers in our house with TVs and radio since the '70s. The only real reception issues we had were with the weather.

 

Adrian

[deadlyduck]

What colour are the suppressors ?,are they the same colour in Hornby/Bachmann ?.Thank you

[JJGraphics]

What colour are the suppressors ?,are they the same colour in Hornby/Bachmann ?.Thank you

 

Colours vary due to the different sources of supply used by the manufacturer of the model.

I have even seen different colour items in two identical locos purchased at the same time . . .

[Oldddudders]

When I ran my DC layout in Kent, my wife always knew because of interference on the tv. Changing to DCC in the late '90s saw that pretty much disappear.

 

Back in the old 405-line tv days, shortly after the Ark landed, almost anything electrical could be a cause of interference. Slot cars were a real pain if not suppressed. As a member of Reigate Model Car Racing Club in the mid '60s, the effect of cars on the tv in the adjoining pub was dramatic. Mind you, a nearby Black and Decker drill could be pretty disruptive to a tv picture in those days, too.

[deadlyduck]

So how do you identify the suppressor,that needs removing ?

[TheWeatheringMan]

When I ran my DC layout in Kent, my wife always knew because of interference on the tv. Changing to DCC in the late '90s saw that pretty much disappear.

 

Back in the old 405-line tv days, shortly after the Ark landed, almost anything electrical could be a cause of interference. Slot cars were a real pain if not suppressed. As a member of Reigate Model Car Racing Club in the mid '60s, the effect of cars on the tv in the adjoining pub was dramatic. Mind you, a nearby Black and Decker drill could be pretty disruptive to a tv picture in those days, too.

Hi,

Its not actually anything at all to do with whether the tv broadcasts are 405 lines or not.

In the days of AM radio (short wave / medium wave / long wave) interference was a major problem and model railways were often the culprit.

Regulations controlling the emmision of interference were contained in the Wireless Telegraphy Act 1949.

This applied also to interference to tv broadcasts as well and the old 405 line system was transmitted on VHF, this being the relevent matter

Model railway manufacturers tended to fit a 'belt and braces' supression in order that their products stayed well within the requirements of the Act.

With the advent of firstly VHF radio broadcasts and later UHF (625 lines) television the problem of interference became less because VHF radio is transmitted by FM (Frequency Modulation) which is much less prone to interference than the older AM (Amplitude Modulation) used for short/medium and long wave. Likewise UHF (Ultra High Frequency) tv broadcasts are again less prone to electrical interference than VHF.

This is a slight simplification as VHF television was transmitted in two different frequency bands (Bands 1 and 3 - with VHF/FM radio on Band 2)

The comical aspect to all this was that in most transmitter areas ITV was slightly less prone to interference than BBC tv due to ITV being, in most areas, on the higher frequency Band 3 VHF.

BBC2 was always the least effected as this was only ever on UHF as the channel commenced UHF broadcasts in the UK in 1966. The duplication of (the now) BBC1 and ITV on UHF at 625 lines began in 1969 at the same time as the begining of colour on those channels, BBC2 having begun early colour broadcasts in 1968.

 

Obviously the position has changed greatly now that terrestrial tv has gone digital as this system is much less prone to the kind of interference that model railways could cause.

However most of the requirements of the 1949 Wireless Telegraphy Act still apply in later Acts so manufacturers are forced to still fit now virtually needless supression.

 

Clearly in view of the situation with american models they dont have the same requirement in law perhaps.

I wonder if one of our good Members over the water could answer the question.

 

Regards

[Dieseldog]

What colour are the suppressors ?,are they the same colour in Hornby/Bachmann ?.Thank you

The ones I took off the Bachmann 03 was yellow in colour, I would post a pic but cause I'm using the iPad the files are always too large, anyone any ideas how to solve this and I will be able to post some pics.

[Dieseldog]

So how do you identify the suppressor,that needs removing ?

I'm sure someone will put me right if I'm wrong but they bridge to two motor connectors together (there maybe more than one) and I think they are referred to as either a capacitor or shunt.

Maybe a bit vague but I am new to this as well, I need explanations in pigeon English and not so much jargon at times.

[34theletterbetweenB&D]

...I need explanations in pigeon English ...

Really, you don't. There's simply no way to adequately convey the necessary information without the specialised terms - or jargon - applied to describe its functionality. This presents a basic choice, and I will use an excellent coinage by Terry Pratchett to hopefully make it clear.

 

You may choose not to acquire this specialised knowledge, and thus remain a knowlessman.

 

Or, you can study a little, and better understand what's what. GCSE Physics is all you need for everyday life. (I'd make achieving a pass in this subject a requirement to obtain a provisional driving licence, but cannot get the government onside...)

[buffalo]

So how do you identify the suppressor,that needs removing ?

 

As an example, here's a Bachmann 4F with its clothes off:

 

 

The capactors are the yellow/orange things toward the front of the motor. In this case, and many others, there are three of them. One between the two motor terminals and one from each terminal to the motor body. All three of these can be removed.

 

At the back of the motor are two inductors (sometimes misleadingly called shunts) hiding beneath some tape. These are blue in colour with coloured bands indicating the value of the inductance. These are often confused with resistors, they look similar but are quite different electrically. Sometimes, often with older models, these will look like coiled wire (which in fact they are) rather than the ecapsulated type seen here. Inductors may also be removed, but they must be replaced by a wire link as they are fitted in-line between pickups and motor..

 

Bear in mind that this is just one example, though many models are quite similar, perhaps with different coloured components.There are rarely any other electrical components fitted near the motor, but many DCC-ready models may have these mounted on a small printed circuit board together with the DCC socket. In other cases, mostly diesel/electric prototypes, there will be a larger printed circuit board that also includes circuitry for lighting etc.

 

If in doubt about any particular model, just show us a photo and ask.

 

Nick