 Joined: 01/02/2004(UTC) Posts: 7,464 Location: Scotland
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Using the function decoder to light my coaches I am connecting the red wire to the pickup and the brown to the ground then from the decoder brown/red and the orange to the light bar. This gives on and off on f1 and works fine. Then for the second coach I use the current coupler taking the brown red to the second light bar. I then connect a ground contact to the second coach and then to the light bar on that coach.
The result is a constant flicker on the second coach only which appears to be caused by the ground contact on that coach but I cant think why or how to avoid this.
Any help is appreciated.
David |
Take care I like Marklin and will defend the worlds greatest model rail manufacturer. |
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 Joined: 19/12/2003(UTC) Posts: 1,205 Location: Swindon, Wiltshire
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Hi David
This is a well-known and well-documented problem. The current in the digital world is not a "pure" DC current since it is "interrupted" by the digital signals which have to be communicated to the decoders via a reversal of polarity. So whereas there is mostly +20V (approx.) on your rails, every now and then it's -20 when a digital signal comes along. This happens many times per second, and the visible sign is the flicker that you see on your second coach.
The reason why your first coach is OK is because you're using the orange wire instead of ground (the rails) directly. Now, the orange wire supplies a straight, smooth +20V all the time, so there is no flicker in that coach.
So the solution is to somehow get orange in the other coaches as well. Some common ways are:
1. Use two-pole current-conducting couplers that can carry both the brown/red and the orange.
2. Fit sliders to the remaining coaches and "make your own orange" by connecting slider and ground via 2 diodes (disadvantage: you're back to a slider per coach).
3. Use a diode and a capacitor between ground and brown/red in each coach; the capacitor will "smoothen out" the digital signal. |
Richard |
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 Joined: 13/05/2002(UTC) Posts: 676
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Quote:[size=1" face="Verdana" id="quote]quote:Originally posted by rugauger
So the solution is to somehow get orange in the other coaches as well. Some common ways are:
1. Use two-pole current-conducting couplers that can carry both the brown/red and the orange.
2. Fit sliders to the remaining coaches and "make your own orange" by connecting slider and ground via 2 diodes (disadvantage: you're back to a slider per coach).
3. Use a diode and a capacitor between ground and brown/red in each coach; the capacitor will "smoothen out" the digital signal. See previous post and cartoon by perz: https://www.marklin-users.net/fo...fault.aspx?g=posts&t=181http://home.swipnet.se/perz/funcret.gifAdmittedly, a slider per coach is not very attractive, but it may be good to know that it works. I would prefer #1, using Viessmann two-pole couplers. |
*Bart |
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Joined: 01/02/2004(UTC) Posts: 7,464 Location: Scotland
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Hi. Thanks for info. I did use two pole couplers but change to the single pole which is better than Viessmann which are not always reliable.
Marklin in their instructions with the decoder appear to indicate that using their single pole coupler other coaches can be added..they say (First coach would use its existing ground as the ground return ) This does not make much sense to me.
What would happen if only the red and brown were connected to both the pickup and ground and then to the lighting bar...leaving out the brown/red and orange. F1 would no longer work but would the lighting would be turned on and off just by selecting the decoder address.
I am sure I have had this working in the past without any further connections but may be wrong.
David
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Take care I like Marklin and will defend the worlds greatest model rail manufacturer. |
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 Joined: 16/08/2006(UTC) Posts: 5,382 Location: Akershus, Norway
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I always use a small mono stable relay to feed the cars with current for the light.
Red/brown to one end of the relay coil.
Orange to the other end of the coil (positiv, if mentioned on the relay).
Then the relay is controlled by the decoder.
A 24 volt mini one-pole relay should do the trick.
Red from the pick-up shoe to one end of the relay switch,
the other end of the relay switch supplies the track current through your train.
If using normal bulbs, the light will be flicker free.
You also redusce the load to the decoder.
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Best regards Svein, Norway
grumpy old sod
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Joined: 01/02/2004(UTC) Posts: 7,464 Location: Scotland
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Many thanks Svein.
My problem was that Marklin indicated that it was possible just using their decoder but it is clear that this is not possible and I will now use suggestions as above.
Thanks for assistance guys
David |
Take care I like Marklin and will defend the worlds greatest model rail manufacturer. |
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Joined: 19/12/2003(UTC) Posts: 1,205 Location: Swindon, Wiltshire
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It depends on a) how many coaches you have and b) what the lighting method is The c96 should be good for at least two coaches, even if the lighting is by light bulbs. Also, light bulbs flicker less than LEDs (but still a little). So it is possible to run the lights straight off the decoder. If lighting is by LED, then the flicker needs to be controlled using one of the methods mentioned earlier. However, due to the lower power consumption of LEDs, it should be possible to run 4-5 coaches off the decoder. But I agree that, for future expansion  , the relay solution is perhaps better. Bear in mind, though, that if LEDs are used, the flicker problem still needs addressing! |
Richard |
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Joined: 16/08/2006(UTC) Posts: 5,382 Location: Akershus, Norway
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Quote:[size=1" face="Verdana" id="quote]quote:Originally posted by rugauger
Bear in mind, though, that if LEDs are used, the flicker problem still needs addressing! Correct, as the LED uses only one half of the waveform, the upper or the lower, depending on how it is connected. My suggestion is to solve this with a small bridge rectifier in each coach. |
Best regards Svein, Norway
grumpy old sod
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