Led's to be programmed for Swiss locos

[river6109]

I have model HO trains and copy would like to install the Swiss light change from 3 white in the front to 1 white in the back. What I have done before and without any problems I've bought a 1N4007 diode and installed it in such a way, when switching directions the light changed from 3 to 1 and visa versa when in fact 2 Led's are combined in the forward and reverse position and 1 led is always the opposite e.g. the loco is running forward, the decoder is set for lights forward whereas the backlight is set for reverse., since than for some unknown reasons the 1N4007 has changed and it lets a small amount of reverse voltage through and this lights up the single white marker light but also lets a small amount of voltage through to light up the other 2 lights enough to notice it. what diode can I use to prevent any voltage going through, thanks, John

 

[Arouse1973]

Hello. Sorry I don't understand what you want to do. What does this mean?

"I have model HO trains and copy would like to install the Swiss light change from 3 white in the front to 1 white in the back."

Thanks
Adam

 

[Martaine2005]

Hello. Sorry I don't understand what you want to do. What does this mean?

"I have model HO trains and copy would like to install the Swiss light change from 3 white in the front to 1 white in the back."

Thanks
Adam

Hey Adam, that's because he's from Ozz...
Sounds like he's got a 'Bobby Dazzler' and a 'wun Hung Lo'.
I hope his sense of humour is not 'as dry as a dingo's donga'. Or a 'pomms bath mat'...

Sorry, I couldn't resist it...It's the child in me..

Martin

 

[Martaine2005]

I think you need a diode in series with the single rear LED.
Why are all the 'blau' connected?
Seems like the two front leds are in parallel and the rear led is in series with the fronts.
EDIT: No it isn't. Only fronts are. Your shematic should work as it is.

Edit2: All you need if Gelb and Weiss are positive rails is a second diode series connected to the diode you have now, but the opposite way. That should work.
So gelb is the Anode and Blau is the Cathode, while reversing the train, Weiss is the Anode.

Martin

 

[duke37]

A 1N4007 should be plenty good enough but if it is leaking, then it has been zapped. The train can produce high inductive voltages.

A pair of Zener diodes, about 20 or 30V back to back across the input would trim the pulses.

Do you control speed with pulse width modulation? If so, an electrolytic capacitor after the steering diode will hold the voltage up between pulses and give a more constant light.