"Custom Signals" Operation problem flashing red/green

Are you trying to emulate prototype signals or just show the position of switches? I ask because it would be very unusual in the real world to see two Medium Clear signals in a row as shown in your photo.

For troubleshooting...

• What is controlling the signals that are switching colors, a relay or an electronic circuit?
• Is the timing of the color change random or precisely rhythmic?

What are you using to power the signals?  If you are using anything other than a filtered DC power supply, you can get the kind of flashing you describe.  Terry Christopher once demonstrated this behavior to me by using an AC transformer combined with a bridge rectifier to provide DC.  Some of the signals flashed.  Changing this power supply to a filtered DC supply stopped the flashing.

My signal system is powered by an old computer power supply, which provides filtered and regulated DC.  I have over 50 signals and no flashing.

My system shows switch direction and if the block after the signal is occupied or not. It is designed to be prototypical, with red, yellow and green.

green = next 2 blocks are clear

yellow = next block is clear, then you may need to stop

red = stop, next block is occupied

In the photo, I use these signals to show switch position only, feeding my 5 track yard. From the picture angle show, you cannot tell how the switches are thrown, so the signals let the operator know which yard track he will end up in, based on current switch position.

The signals use the circuit boards that come with the Custom Signal signals, which is the same as the boards used by Atlas.

My signal boards are powered by AC power, about 12VAC from aux posts on a Lionel 1033 transformer. The track detection to the circuit board is 5VDC.

I only have a few signals that sometimes flash, for some switch positions, which they should not do.

I could try using a computer DC power supply. I imagine that I would simply cut the power plug to the laptop, and then connect to a 2-wire extension to reach my circuit boards, which are in two different locations on my layout.

Would I need to use my meter to set the polarity of the 12 VDC computer power supply?

I have about 56 signal lights and 21 switches.

Bob how do you filter DC?

Billy C

I had a similar problem  as described above with a DC power supply which gave half wave rectification, and had a few signals flash yellow. I suspected that since it was not filtered DC some AC was getting through most likely what is called AC noise ripple. I added a 100uf capacitor in series with the input power and that filtered out any AC noise. At my next visit to York I spoke with Terry Christopher about this and he confirmed that the AC leaking noise ripple ( whatever you want to call it ) was indeed the problem causing the LED's to change and flicker. He said a 10uf cap would do fine, I said I used 100uf, He said all the better........If you use a computer power supple with pure filtered DC. Your problem will be solved.

and to answer the question on how do you filter DC .......... A capacitor in series with the output of the power supply will stop, clean off or filter any spurious AC from the half wave rectifier.

Enjoy

Frank               

" I added a 100uf capacitor in series with the input power and that filtered out any AC noise. "

In my experience, a series capacitor basically allows AC to pass, and blocks DC.  Any power supplies that I have used that provided filtered DC used a capacitor in PARALLEL with the OUTPUT of the supply.

I would like to hear your explanation of how a capacitor in SERIES with the INPUT of a power supply is creating filtered DC to operate your signals. What power supply are you using?  Can you provide a schematic or a model number?

I think LVFan has “series” and “parallel” confused. You cannot put a capacitor in series with a DC load. That will not work.

Filtering DC is easy. Just add a 100 Mfd (or larger) cap in PARALLEL with the load and you’ve got filtered DC.

The + lead of the cap goes to DC plus, the other lead to ground.

to clarify the discussions above:

1) If I use a computer 12VDC power supply, do I need to add a capacitor to filter out any AC noise?

2) Do I need 12VDC, or would say 5VDC be sufficient to run the signals? This would mean I could use a wallwart.

3) If I use the 12VAC from my 1033 transformer, can I add a capacitor or other "stuff" to convert the signal from AC to DC?

Thank you for the various inputs to this discussion. Some good ideas and suggestions.

Yep my mistake it was getting late and I was tried.... parallel is the correct way for the capacitor to be installed.  I apologize for the error and any confusion it may have caused.

Sincerely

Frank

Terry used to supply this half wave filtered setup if you were going to run his signals and other boards like the TSCs off AC power: