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Hi All, I Have just joined this forum and have a query. I searched yesterday for interference but found little reference. This is the problem I have. A mad moment a few days ago caused my to fetch my youngest son's hornby train set down from the loft, Having been there for some 20yrs. I cleaned the rails with a rubbing pad and got the system running quite good. However some sparking is noticeable from wheel areas occasionally. The main thing is that there is interference of flashing lines across the tv at the other end of the house. Would this be due to dirty rails/ connections or a more fundamental problem with the loco or power supply. Bearing in mind the age of the system. The system has not had a lot of use from new, at a guess about 15-25 hrs maximum running time. Any help /advice would be appreciated. I apologise if this is a repeat of any discussions already on the forum but If there is I was unable to find them. P.S. I am considering buying a Bachmann DCC starter set as I would like to try digital at as low a cost as possible in case it ends up like this set buried for 20yrs. I am a little older now so it may not happen. My son has just turned 29 and I will soon be 64 so maybe we will become interested this time especially as we have a spare room to use. Thanking you Martin
 

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Hi Martin, welcome to the forum.

As your loco(s) are quite old, they probably don't have any suppressors on the motors. These days the manufacturers add capacitors to the motor terminals to reduce TV interference.

When we test some DCC decoders and locos, we often remove capacitors to improve the running as the DCC circuitry on some decoders has some suppression built in.

You could as a model shop who installs decoders to add a capacitor to your loco to see if that helps. You could add a DCC decoder to it and ruin it on your new DCC system when that arrives, you may find that the interference goes away. No certainties here, you'll have to try various options out.

Check out some of the shops that advertise on our forum. Most of them have a decoder installation service.
 

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The sparking you are seeing at the wheels is the visible evidence that you have a "spark gap generator". As this answer on Yahoo answers explains, a spark gap generator is a very good source of radio waves. These are what are interfering with your TV. It doesn't help that the two rails of your track are acting as an aerial.

The cure is to ensure that the circuit between your power supply and motor is not broken. As you have already cleaned the track, my guess is that the wheels on the locomotive are the most likely cause of dirty deposits and so I would check to see if they are clean.

One of the counter measures manufacturers apply to counteract the rails acting as an aerial is to include suppression circuits in the power clip, but I'm guessing that you are using the one which came with the set.

Another factor is the strength of the TV signal in your area and the alignment of your TV aerial. I grew up in a weak TV signal area with the result that during high pressure conditions in the summer, model railway running was banned because it really messed up the TV signal.

It is important to note that all the counter measures for interference change completely when you use DCC. The most important but least obvious thing for train set users is the power clip I mentioned earlier. For DCC, the suppression circuit in a DC power clip interferes with the DCC signal and since it was designed for the completely different DC wave form is totally inappropriate. This is why a similar but internally different power clip is supplied with DCC sets.

Basically, cleanliness is the route to zero interference. Any sparks anywhere in the circuit from power controller to motor indicate a source of interference.

If you are really intent on getting a DCC set, you might be better to buy it now as the wheels and track will come "factory clean" and I would be surprised if you had the same problems. I am not making any promises though!

David
 

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Discussion Starter · #4 ·
QUOTE (Doug @ 18 Sep 2008, 20:29) <{POST_SNAPBACK}>Hi Martin, welcome to the forum.

As your loco(s) are quite old, they probably don't have any suppressors on the motors. These days the manufacturers add capacitors to the motor terminals to reduce TV interference.

When we test some DCC decoders and locos, we often remove capacitors to improve the running as the DCC circuitry on some decoders has some suppression built in.

You could as a model shop who installs decoders to add a capacitor to your loco to see if that helps. You could add a DCC decoder to it and ruin it on your new DCC system when that arrives, you may find that the interference goes away. No certainties here, you'll have to try various options out.

Check out some of the shops that advertise on our forum. Most of them have a decoder installation service.
Thanks Doug, Any comments on my choice of dcc system?
 

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Discussion Starter · #5 ·
QUOTE (dwb @ 18 Sep 2008, 20:52) <{POST_SNAPBACK}>The sparking you are seeing at the wheels is the visible evidence that you have a "spark gap generator". As this answer on Yahoo answers explains, a spark gap generator is a very good source of radio waves. These are what are interfering with your TV. It doesn't help that the two rails of your track are acting as an aerial.

The cure is to ensure that the circuit between your power supply and motor is not broken. As you have already cleaned the track, my guess is that the wheels on the locomotive are the most likely cause of dirty deposits and so I would check to see if they are clean.

One of the counter measures manufacturers apply to counteract the rails acting as an aerial is to include suppression circuits in the power clip, but I'm guessing that you are using the one which came with the set.

Another factor is the strength of the TV signal in your area and the alignment of your TV aerial. I grew up in a weak TV signal area with the result that during high pressure conditions in the summer, model railway running was banned because it really messed up the TV signal.

It is important to note that all the counter measures for interference change completely when you use DCC. The most important but least obvious thing for train set users is the power clip I mentioned earlier. For DCC, the suppression circuit in a DC power clip interferes with the DCC signal and since it was designed for the completely different DC wave form is totally inappropriate. This is why a similar but internally different power clip is supplied with DCC sets.

Basically, cleanliness is the route to zero interference. Any sparks anywhere in the circuit from power controller to motor indicate a source of interference.

If you are really intent on getting a DCC set, you might be better to buy it now as the wheels and track will come "factory clean" and I would be surprised if you had the same problems. I am not making any promises though!

David
Thanks DWB, Good advice. Any comments on suitability of dcc choice? Thanks Martin
 

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QUOTE Any comments on suitability of dcc choice? Thanks Martin

The Bachmann system is considered a good introduction to DCC. If you like it, you will "out grow" the controller that comes with the set. As for where you should go after that, this is a regular question in the DCC section. It just so happens that Doug is wondering what to upgrade to from his Lenz 100 which was "the business" not so many years ago.

David
 

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Locos have had supressors as far back as I can remember, late 50s early 60s and they certainly had them in the 80s. Not being used for 20 years is probably the cause of the sparking. Cleaning the wheels has already been mentioned, but don't forget the power pick-ups on the wheels too. After cleaning the track with a track rubber I wipe over with cleaning fluid too. You'd be surprised how much dirt it picks up after the track rubber is used.
Is your TV analogue or digital? I find there's much less interference on a digital tv.
 

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Hi Martin

Welcome to the forum.

The sparking of the motor brushes , can even cause TV interference
when I put new brushes in my loco's (when converting to DCC usually) I run the motor for a short time in both directions
clipping crocodile clips to the motor (with no other wiring attached) and still get TV interference on one channel (our ABC1)

So major complaints from other family members

After the loco is converted to DCC - No more interference

A good excuse to go for DCC

Regards Zmil
 

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QUOTE (Doug @ 18 Sep 2008, 19:29) <{POST_SNAPBACK}>As your loco(s) are quite old, they probably don't have any suppressors on the motors.

AFAIR all (certainly the old Triang) always had suppressors but it's very possible that they have either been removed or have lost their effectiveness over time.

As these old loco's only had pickups on two wheels (on the "insulated" side) it's most important to get good contact on the wipers and wheel treads by making sure everything is clean & the wipers are making good contact with the back of the wheels.

Any dirt on the commutator/brushes (don't forget the commutator segments) should be removed (avoid using any form of oil based "lube" anywhere on the locomotive) and all should be well.

It's also worth checking the TV signal - if it's weak then some attention here will help too (if it is weak you will certainly have to get it sorted in time for the demise of analogue TV).

Hope this helps.
 

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I would like to suggest that any locos that have been unused for a long period of time should be carefully inspected and lubricated before being run. Old oil tends to become rather thick and can lead to excess current being drawn and therefore excess heat being generated, the excess current being drawn may be a partial cause of the sparking that is seen and the heat will tend to cause motor failure. Motors whizzing round at high speed with no lubrication on the bearings is also a cause of early failure.

Less interference on digital TVs? I believe digital TVs have error correction circuits which would help to filter out interference. The Freeview (terrestrial) digital TV service is (I am told) not running at full power yet, it will be switched to full power once the old analogue service is switched off. A side effect of this is that all those old TV aerials that have not been upgraded for digital service, will probably (in many cases) then work perfectly with a digital signal! (so I am told)
 

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''I would like to suggest that any locos that have been unused for a long period of time should be carefully inspected and lubricated before being run''.

Do locos have to have a liquid lubricant applied to the gears i wonder, as 'grease em ' is recomended for use on layout general use, it works well on new couplings running smoothly so can it be used on locos
 

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QUOTE (upnick @ 20 Sep 2008, 20:12) <{POST_SNAPBACK}>''I would like to suggest that any locos that have been unused for a long period of time should be carefully inspected and lubricated before being run''.

Do locos have to have a liquid lubricant applied to the gears i wonder, as 'grease em ' is recomended for use on layout general use, it works well on new couplings running smoothly so can it be used on locos


What type of lubricant is it ?
 

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Hi Brian,

Its a powdered graphite lubricant.
 

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QUOTE Could be ideal for using on sticky close coupling mechanisms

That's what Kadee sell it for.

David
 

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QUOTE (zmil @ 21 Sep 2008, 03:28) <{POST_SNAPBACK}>Hi All

RE: Graphite Lube

The only thing to be careful about , is that Graphite is a conductor
and may cause a short if it works its way into the loco wiring/motor etc

Regards Zmil

Hi Zmil,
Thats a thought the conductivity issue, give it a miss then and keep for the couplers ........ applying away from the layout has another plus 'Grease em' sparkles when in the right light dont think it will enhance the scenics
 
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