Wiring PRR Position Ligth signal to work with a rotary switch (bulb and LED)

[peteski]

I’m sure this is meaningless to most of you but to me this is a major milestone: I finally got 3 of the Pennsy signals I have had for 40+ years wired. They were on my old layout unwired and on my current layout in their current (prototypical) positions for almost 10 years. They are grossly oversized but I still like them.

1)   The old signals have 5 wire leads. One common and one each for the center (1 bulb), vertical (2 bulbs), diagonal (2), and horizontal (3) (includes the lower post bulb also). I currently have them wired to an Atlas selector which means I have to turn on the center bulb and also chose another aspect to turn on. Can someone tell me what kind of switch (how many poles; [4 throws (off/vertical/diagonal/horizontal)]) and how to wire the center light to come on with vertical/diagonal/horizontal positions without shorting and turning on all bulbs?) (@peteski where are you when I need you?)

2)   While I am at it: How do you hook up and control the newer LED version? It has 3 wires (1 with a resistor). How do you change positions and what kind of switch do you need? The instructions that came with it are pretty useless.

3)   And while I am asking is there a circuit that would show where adjoining block of separate throttles are both aligned to the same direction (vertical); aligned to opposite directions (horizontal) or one side off (diagonal)? All using track power (I do not have block sensors. It is a DC layout.)

I still have 2 old and 3 new signals that need to find a home on the layout

@rickb773

Hi Rick,
Yes, all the things you are asking for should be doable.  I'll answer the signal questions here.  As for the block indication, why don't you start another thread about that in tis  section of forum and I or someone else should be able to address the question.

What you are asking for for the old signals is easily done with some diodes.  Sort of like the diode matrix some modelers for throwing switches in yard ladders.

But I'll need more details.
What type of power supply are you usioing to power them?  AC? DC?
Do you have the common wired to positive or negative side of the power supply (if using DC).
If you are using AC power, the diode matrix will not work - you will have to switch to DC.

Using diodes you can keep the switch you are already using and the center light will light up automatically.

If you can draw a diagram of you current circuit (even pencil drawn, on a piece of paper, then scan it or take a photo of it, and post it to the forum), that will be very helpful.

I need more info about the LED signals. Who made them?  Are the instructions available online?  If not,  can you scan them and post here?
I'm also not  certain how you can get 3 different indications from those with only 3 leads. Again, I need more info.

[Point353]

I need more info about the LED signals. Who made them?  Are the instructions available online? 

Looks like NJ Int'l 2045: https://njisignals.com/collections/n-scale-signals/products/2045
Recommended operating voltage is 9-14 VDC. https://njisignals.com/pages/2015-show-schedule
Beyond mentioning common-anode type connection, wiring instructions or schematic do not appear to be available online.

[peteski]

Hmm... the puzzling thing is how can it indicate 3 aspects with a 3-wire hookup where one of the wires is common.

EDIT: Um, wait - I think that photo shows 3 bare wire ends and one with a resistor soldered to the wire?  That makes more sense.

[rickb773]

Hi guys,

This is a DC block layout withOUT any block sensors. All block are controlled by SPST Ctr off toggles to 2 power packs.
I know only very basic electrical concepts. I do NOT know what anodes/cathodes are so the explanations are going to have to on a 5th grader level. 

The old signals say they will run on 9-14 volts DC but I am running them at around 3 volts which make them light good enough. The bulbs get very hot in a short period of time.

The old signals have 5 wires, one red and 4 black.
The red is a common.
The other 4 are for the Center light, 2 vertical lights, 2 diagonal lights, and 2 red horizontal lights and the light on the lower post.
I have the latter 4 wires individually going to the 4 connections on the Atlas selector.
I need to turn the center bulb on with a separate switch (#1) and then throw one additional switch (#2,3,or 4) to give an appropriate signal indication.

I would like to be able to have an off position and the 3 different signal indications without having to do a separate switch for the center bulb. So far any connections I have tried to gang results in all 7 bulbs coming on at the same time.


The new signals, NJ Intl 2045 have 3 wires (one includes a resistor) and the instructions make no sense to me.

Instructions for new (2045) and old (2040):


Old signals connected to an Atlas Selector:


Thank you for your assistance!

[peteski]

Thanks for those instruction scans.  You're right - not helpful here.  The instructions don't even mention the Position Ligth LED signal, but least they mention "common anode" (common positive).

Diodes are like valves, only allowing DC current to flow in one direction.  Using them to power the center bulb will prevent all the bulbs coming on when any aspect is selected by the Atlas selector.  I'll draw you a diagram (that a 5th grader will understand) and post here when ready. 

Now onto the LED signals.  I can't see way that you can get all 3 aspects displayed with just to wires plus a 3rd common positive.

Let's test out the LED signal. Take a 9V battery and hold the resistor lead on the positive battery terminal.  Then take one of the bare wires from the signal and touch it to the negative battery terminal One of the aspects should illuminate (including the center LED).  Then release that wire, and try touching the other bare wire to the negative terminal.  That should light up another aspect.  That is all you get with those wires.
I suppose you could touch both bare wires to the negative terminal, but I'm pretty sure that you will see both aspects light up (not the 3rd one).

As far as the block identification questions, I really think you should create a separate thread for it.  Or are you asking of the block polarity can be used to control the signal aspect?

[peteski]

Here is a simple hookup diagram of a circuit which will automatically light up the center bulb when any aspect is lit. I color-coded the wiring to make it clearer.
Now the 4th selector switch is unused. You could use it to control the small signal head mounted on those masts.



The black components are diodes.  The white band denotes cathode (you don't really need to worry about it - just follow the wiring diagram). I assume that you use common positive wiring. If not, you can either switch the power supply leads or flip all the diodes in the circuit (so the white band on the diodes points towards the signal).

The bulb in option 1 will only get 2.3V because of the voltage drop at the diodes. If it is noticeably dimmer (I suspect it will be), then I recommend using option 2. The 3 additional diodes are added simply to drop 0.7V going to the bulbs in each aspect, to match their brightness to the center bulb.  If the power supply is adjustable, you might want to crank up the voltage a bit to compensate for the diode voltage drop.

As far as diodes go, those are very basic silicon rectifier diodes. They have been around for many decades and very inexpensive.  The 1N400X series has a range of diodes with different maximum reverse voltages. They go from 1N4000 through 1N4007.  Any of those will work in this circuit.

You can find those at any electronic supply company (like Digikey or Mouser Electronics), and electronic surplus suppliers like Electronic Goldmine or All Electronics to name a few.  I think even Walthers carries those diodes.  If you want, I can point you to some specific sources.

[peteski]

So what happened @rickb773  ?  Suddenly lost interest in the project?

You profile shows: Last Active:    Today at 11:02:11 AM

[rickb773]

So what happened @rickb773  ?  Suddenly lost interest in the project?

You profile shows: Last Active:    Today at 11:02:11 AM

Not in the least!
Wife decided that "I wanted to" pull out 7 bushes (mixed in with 2" tree roots) and replace them with 4 new bushes.
Since this was to be "our anniversary project" it suddenly came to the top of the To Do list.

I was expecting a magic solution of some sort of 4 position rotary switch (Off, Grn, Yel, Red) to be the solution but I suppose that would still require require the 6 diodes. Which in turn would require some sort of board (for each signal) and I am running out of under layout space for the boards.

I will soon test the new LED position lights but I am terrified that I will do something backwards and burn them out.

Promise tests by the weekend! (Even though the "Am I Blue" thread triggered ny ADHD.)

[peteski]

Not in the least!
Wife decided that "I wanted to" pull out 7 bushes (mixed in with 2" tree roots) and replace them with 4 new bushes.
Since this was to be "our anniversary project" it suddenly came to the top of the To Do list.

I was expecting a magic solution of some sort of 4 position rotary switch (Off, Grn, Yel, Red) to be the solution but I suppose that would still require require the 7 diodes. Which in turn would require some sort of board and I am running out of under layout space for a board.

I will soon test the new LED position lights but I am terrified that I will do something backwards and burn them out.

Promise tests by the weekend! (Even though the "Am I Blue" thread triggered ny ADHD.)

Good to hear that it was Honey-do chores that had you away from model railroading.

Yes, there ais another altenrative (like using  a rotary switch with 2 sets of contacts), but I think that would be more complicated than using your existing components and adding bunch of 10 cent diodes.  To me this is the most "magical solution", and it is very hard to blow those diodes up.  Using a circuit board to hold the diodes would be nice, but you can just "wing it" and have them hanging off the Atlas selector.

As for testing the LED signal with the 9V battery, you can't blow up anything unless you bypass the resistor that is attached to the common lead. If you follow my instruction, nothing will burn up (even if you get polarity backwards).  Try having some more confidence in yourself - you can do it!  After all, you build and wired your layout - that is quite a feat by itself. 

[rickb773]

@peteski As for testing the LED signal with the 9V battery, you can't blow up anything unless you bypass the resistor that is attached to the common lead. If you follow my instruction, nothing will burn up (even if you get polarity backwards).

OK you talked me into it and I owe you an apology.
When I unraveled all the wires: there are: Eureka - 3 wires besides the one with the resistor.
Suddenly the world is much clearer!

And they all turn on the center light individually as they do the 3 aspects, so they have somehow solved the center light issue in a smaller signal.

So I should now be able to use an Atlas Connector switch (instead of wasting half of the Atlas Selector.

What I do not understand is that ALL the wires appear to be uninsulated brass/copper wire but they do not short each other.
Evidently there now exists wires that only conduct at the end???

Anyway, thank you, thank you, thank you for your help.

I will now take your advice and start another thread for the block indication question.

[peteski]

I noticed that you are a bit leery of dealing with electrical and electronic items, so I wanted t reassure you that you won't burn anything up.  I'm also glad that there was a 4th wire on those LED signals. Makes sense now. No need for appologies Rick.

The reason that they were able to get the center light to light up without a separate wire for the center LED is because LEDs are diodes (Light Emitting Diodes).  So they can be wired inside the signal in a way similar to the diode circuit I designed for your bulb-based signal.

But you will probably need more than 3V to get the LED signal to light up.  It will likely need about 6V or higher.

Those thin wires are called "magnet wire" or "enameled wire". It is a thin copper wire with a very thin layer of insulating lacquer or enamel applied to its surface.  That is why they do not short out to each other.  They are also a bit more fragile than standard insulated wire, so be gentle with them.  If you look carefully, you will notice the their ends are silver in color. That is because they were tinned (and that tinning process strips the insulating enamel, exposing the bare wire).

[mmyers]

Many years ago I built a set of circuits from a series of articles in N Scale Magazine by Rich Weyand. I believe it was around 1990 or so. I used optical detectors in each block to control the boards connected to a couple of dozen NJ Position light signals.(the old ones with bulbs). As I recall, all blocks would normally show green -proceed. An occupied block would stay green for the direction the train was proceeding unless the next block or the one ahead of that was occupied. Previous block would go red, the block before that would go yellow. As the train proceeded, the preceeding blocks would change. Third block back would go back to green unless occupied. It worked good but there was a lot of wires. The Weyand circuit that I built was able to handle traffic in both directions. At the time there were boards available along with a list of Radio Shack parts. I perfed mine out on blank boards also from the Shack.
There were other options available too but this was the simplest set up as I recall.
He was selling these kits as Trac Tronics. Not sure if still around. I’ll try to find the series.

Martin Myers

[mmyers]

Found it. N scale Magazine July/August 1996. Page 33

[rickb773]

Here is a simple hookup diagram of a circuit which will automatically light up the center bulb when any aspect is lit. I color-coded the wiring to make it clearer.
Now the 4th selector switch is unused. You could use it to control the small signal head mounted on those masts.



The black components are diodes.  The white band denotes cathode (you don't really need to worry about it - just follow the wiring diagram). I assume that you use common positive wiring. If not, you can either switch the power supply leads or flip all the diodes in the circuit (so the white band on the diodes points towards the signal.

Thank you Mr. @peteski, it works! (Was there ever any doubt? )



I did have to flip the diodes on the breadboard.
(I felt like a kid playing with one of those "34 Electrical Projects in One Kit" Christmas present.)
(But boy, the breadboards have gotten a lot smaller. Where is a cheap source for 20 gauge solid wire?)

Is there a way to tell which is the "common positive" terminal on MRC Tech 4 & Tech II power packs?

[peteski]

I'm glad that I was able to help!
The "accessories" output on model train power pack is an AC output - there is no polarity, so I assume that you are using the track output to power up your signals.  You can check its polarity (where the positive and negative terminals are) using a DC voltmeter.  Hook up the meter to the terminals, crank up  the speed knob and check the reading on the meter.  If the meter shows positive voltage then the meter's red lead is on the positive terminal. 

If you are using the track output for those signals then instead of reversing the diodes, you could  have just flipped the throttle's direction switch for the same result.    If you flipped the diodes than you have now wired the signal to have negative common.  Not that it matters with light bulbs, but if you will be hooking up multiple signals on your layout, it is best to standardize the wiring.  And if you will be adding those LED signals (which are common positive by design), then you should also wire the bulb-based signals the same way. Again, to make the wiring less confusing.

As for the wire, I don't have a layout so I don't buy large quantities of wire.  I buy mine at a local electronic surplus store.  Also, 20 AWG seems a bit heave for using it to hook up signals.  It is also rather stiff and hard to deal with.  I recommend going to a Home Depot (or similar store) and buying either telephone cable (with 4 conductors) or an Internet (CAT5 or similar) cable (with 8 conductors).  Then just remove the outer jacket and you now have bunch of wire.  Or keep it in the jacket for long runs, to make the wiring neater (each conduction is color-coded for easy identification).  That wire is smaller than 20AWG (probably 24 or 26AWG), but perfect for signaling.