Hornby Class 800 flickering lights even with Stay-alive

[Novco007]

Hi All,

 

I have a class 800 with dual sound, using two loksound 4 decoders.  I decided to add some stay-Alice’s to both cars, but specifically it was for the dummy, as it has only one set of pickups and it is fairly light so the sound would stop going over points.

 

I purchased two TRAIN-O-MATIC SPP-N stay-alives and fitted them as per the instructions, it mentions also making some CV changes, but I’m not sure what they are or do and the mention SUSI (not sure what what that is either).  Sound appears to play when the wheels leave the track, but the lights flicker. This occurs on both units, so not sure why, could this to do with these CVS that I’m meant to change?

 

Thanks

 

Chris

[Hamburger]

This can happen if the powerpack delivers too low supply voltage especially if it has just one capacitor.
Usually this has no effect on the motor because the motor control will compensate.
The sound part usually works with a lower voltage anyway and has its own voltage stabilization.
However, the lights outputs are not stabilized.

[NIK]

Hi,

 

I haven't got a Class 800 but the supply to the light electronics may be taken from the track pickups and the decoder(s) only control the lights turning on and off.

 

If so perhaps someone can suggest how to add stay alive functionality to the lighting circuits.

 

Regards

 

Nik

[Novco007]

Thanks for replying, I am guessing that I could add a bigger capacitor to the circuit and a length of wire to hide it a bit further inside the loco.  I may have a look at this a bit later.

40 minutes ago, Hamburger said:

This can happen if the powerpack delivers too low supply voltage especially if it has just one capacitor.
Usually this has no effect on the motor because the motor control will compensate.
The sound part usually works with a lower voltage anyway and has its own voltage stabilization.
However, the lights outputs are not stabilized.

 

32 minutes ago, NIK said:

Hi,

 

I haven't got a Class 800 but the supply to the light electronics may be taken from the track pickups and the decoder(s) only control the lights turning on and off.

 

If so perhaps someone can suggest how to add stay alive functionality to the lighting circuits.

 

Regards

 

Nik

 

[jpendle]

1 hour ago, NIK said:

the supply to the light electronics may be taken from the track pickups and the decoder(s) only control the lights turning on and off.

That's not how it works. You can't apply a raw DCC signal to the lights in a model and then switch them on and off with the decoder.

The lights need DC from the decoder to work, not DCC.

 

Regards,

 

John P

[NIK]

2 hours ago, jpendle said:

That's not how it works. You can't apply a raw DCC signal to the lights in a model and then switch them on and off with the decoder.

The lights need DC from the decoder to work, not DCC.

 

Regards,

 

John P

Hi,

 

That's not what I said. I said the light electronics. Many modern models have circuitry so the lights can be powered from DC or DCC. This requires electronics to as a minimum rectify the DCC to DC (if the lights are LEDs as they often are on newer models).

 

Regards

 

Nick

[Novco007]

Hi All,

 

on reviewing some video I shot, I noticed that the circuit board connected the the LEDs on the body, so would power the cab and central high light, would appear to have diodes and a relatively large capacity installed.

 

at the weekend I’m going to check to see if they flicker, compared to the lower LEDs that are connected on the body.

 

Also, when watching some footage of the dummy car with the sound running and the LEDs showing red, if I lifted the bogie off the track that has the pickups on, the sound will play for a couple of seconds, but the LEDs fade out, about half a second, rather that go off.

 

The instructions for the stay alive https://train-o-matic.com/kb-powerpack.html, in the section for Loksound 4 mentions SUSI, I’ve googled it but not sure what that is and if this and the cvs mentioned would have any affect on this behaviour..

[WIMorrison]

LEDs work happily on DCC when fed directly from the track, just at a lower brilliance than on a rectified signal because the are only working using part of the signal - however you must remember to insert a resistor (or something to limit the voltage) because full track voltage will still kill the LED.

[jdsnape]

1 minute ago, WIMorrison said:

LEDs work happily on DCC when fed directly from the track, just at a lower brilliance than on a rectified signal because the are only working using part of the signal - however you must remember to insert a resistor (or something to limit the voltage) because full track voltage will still kill the LED.

a minor nitpick but the resistor is needed to limit the current not the voltage - https://www.sparkfun.com/tutorials/219