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Discussion Starter · #1 ·
Can any member help on this topic

The clear/red indicator LEDs fitted to the powered/trailer bogy cars, all eight LEDs appear to light up when at standstill within an area where the power has been cut off - on the particular area being powered up by setting the point blades, the indicator LEDs are no longer illuminated.
Disconnecting the power controller unit from the rail circuit in question has no effect in the LEDs illumination being extinguished or powered on.
Through careful checking and mostly trial by error, the disconnection of the Gaugemaster electronic rail cleaner, this error is corrected. The fault has only recently occurred, with no alteration to any circuitry being undertaken or changes to the layout.
Help in tracing this error and corrected would be most appreciated. double00.
 

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Can't really help on this one although I had a few similar "weird" things happen with the combintion of LED's/HF track cleaners/analogue DC before I went "DCC".
Bear in mind that HF track cleaners were brought out before LED's became in common use so maybe they just don't like each other.
It seems that you may be getting some sort of "back feed" somewhere - is there any chance that a wheel is bridging a railgap somewhere ?
Be interesting to know what it is causing the problemm- you could just try running without the HF cleaner.
 

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Bear in mind LEDs are diodes - that is they 'rectify' any AC voltages about, regardless of frequency and will illuminate. So as Brian says, try running without the HF cleaner. If you don't get the effect then that is the problem - the LEDs are feeding off the HF voltage. You say the train is on an apparently 'dead' section, but it is quite possible that there is some form of capacitive coupling somewhere which allows the HF through into that section even with the DC off.
When the DC is switched on to that section the higher DC voltage biases the diode 'off' and stops the effect.

Hope this helps,
Regards,
John Webb
 

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Discussion Starter · #4 ·
Thank you both for your comments, most appreciated.
I failed to mention that the track HF cleaner was disconnected and in doing so the directional LEDs were no longer illuminated. Until the error is found and corrected, the HF cleaner will require probably to be switched off and only used periodically to clean the track. What is most concerning, can the LEDs burn out? as 12v is present from the HF cleaner circuitry when switched on?
 

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Each LED has a resistor in series which limits the current - I suspect the current through the LEDs caused by the HF volts is comparable to the current due to the DC volts when applied. The HF voltage would need to be very high to make the current excessive, so don't worry about it.

Hope this helps,
John Webb
 

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Discussion Starter · #6 ·
John Webb - reply to your last post. Certainly, all lit LEDs appear to be illuminated much less than when the locomotive is running around the layout. When said loco is parked in the "dead" part of the layout - increasing the CPU voltage has no effect on the said LEDs brilliance.
 
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