Modern DPDT Switches for 1122 turnouts

[Civil War]

 Thanks again, another good tip. I have been away all weekend, but tomorrow I will pick up a new drill bit and the 6-32 screws. I already have the taps. I used to do a lot of machine work, so this shouldn't be too hard. Do you know what the frog is made of? Is it brass (unlikely) steel or a pot metal?

 

[lionelsoni]

I have used a 7/64 inch drill for 6-32 x 3/8 inch flathead Phillips screws.  I recommend drilling from the bottom, all the way through the frog, then threading the entire hole.

[Civil War]

lionelsoni

Have you drilled and tapped the frog yet?  Do you know how to do that, or would you like some detailed instructions?

 

 I haven't drilled the frog yet, but that wil be no problem. I just need to get to the hardware store to get a new drill bit of the correct size. Thanks.

[lionelsoni]

There should be two wires.  It looks like they may be in a single insulating sleeve.

That supply looks like it should work.

Have you drilled and tapped the frog yet?  Do you know how to do that, or would you like some detailed instructions?

[Civil War]

 I found another transformer that looks like it puts out 12 volts. Can you take a look?

Transformer

[Civil War]

 Bob,

 OK, I edited the picture in my last post. It only looks like one wire, but are there two wires? I'll look for another power source. Will I be able to use just one HO Train transformer for all my LED indictor lights? 

[lionelsoni]

No, those are the wrong wires.  Notice that they are connected to the control rails, which are the short outside rails that make the non-derailing feature work.  Leave them where they are.  Instead, unsolder the other two wires that are both connected to the center rail.  Then connect both of those two wires to the wire that will come out of the turnout.  Yes, 22 AWG is fine for that.

Be sure to insulate the new connection adequately, and route the wire where it will not get pinched or cut when you put the turnout back together.

I just now went back and looked at the picture of the supplies that you bought.  They are Tyco 899Bs.  I couldn't find any description of the circuit; but I'll bet they are 18-volt supplies with a rheostat in series with the output.  That's the traditional HO way of doing things.  Measuring the voltage with a voltmeter, you wouldn't see any variation, because of the high impedance of the voltmeter.  If that's the case, you can use the one that works with no problem; just turn it all the way up.  The full 18 volts will probably be fine for powering the capacitive-discharge part.  I think that the 18-volt output is a clue that they are intended for slot cars, not trains.

You will need a 12-volt supply to power the LED assemblies that you bought.  If you can find a similar supply meant for HO trains, it should have a 12-volt output, which would work with your LEDs.  Making your own LED circuits, designed to run on the 18 volts or whatever AC or DC supply you want to use is also still an option, instead of getting another HO supply.

[Civil War]

lionelsoni

Have you been able to identify the negative capacitor terminal?  The minus-sign symbols are often inside circles which are themselves inside a stripe with an arrowhead pointing at the terminal.

 

Bob

Yes I see the markings. I received my two HO transformers today. One does not have any DC output. The other has 18 Volt DC output, but it is all or nothing. It is either 18 Volt or nothing. There is no variation of the voltage from the control handle. This doesn't sound normal. Is this OK? 

Below is a picture of the inside of my turnout. As I understand you I connect a new wire (22 gauge OK?) to the two wires from the coil that I will unsolder. The new wire is routed outside and connected to the Negative end of the Capicator. Once this is done I should be able to put the turnout back together, correct?

 

Thanks

[lionelsoni]

The two wires, one from each coil, which were connected to the center rail inside the turnout remain connected to each other after you disconnect them from the center rail and both get connected to the negative terminal of a single electrolytic capacitor associated with that turnout.  I locate mine under the table at the turnout, since both its connections are handy there; but you could put it wherever is convenient for you.

Have you been able to identify the negative capacitor terminal?  The minus-sign symbols are often inside circles which are themselves inside a stripe with an arrowhead pointing at the terminal.

[Civil War]

Civil War

The capacitive-discharge circuit is very simple.  It is an electrolytic capacitor, about 4700 or 5000 microfarads), with its positive terminal connected to the outside rails and its negative terminal connected to the new wire that you installed.  The capacitor's negative terminal is also connected to one side of a number-53 lamp.  The other side of the lamp is connected to a 16-volt (approximately) DC supply, whose positive side is returned to the outside rails.

 

 

Bob,

 OK I got the turnout apart with no damage. My question is: Do I need two capacitors, one for each of the two wires from the coils? Should I run the wires that I attached to the coil wires all the way to the control panel and attach them to the capacitors or should I locate the capacitors below the table at each turnout?

I should have my DC transformer in a few days and we can start working on wiring the toggle switches and latching relays. I am taking pictures of every step of the procedures so I can document the process. I'll post them here once I have one complete working new turnout.

 

[Civil War]

 I got both the transformers for 99 cents. I'll check them out when I get them. They also have an AC output so I might be able to power some small accessories or lights with them.

 

[servoguy]

I just went through a bunch of 1122s and manual equivalents. All of them had bad electrical connections. Some looked like they had been wet, and some were pristine. It didn't matter. They all had loose electrical connections. I recommend you solder all the connections before you reassemble the switches. Work quickly because the plastic does melt a little. The rivet in the center of the fat center rail needs to be soldered at both ends. I used a 4-40 screw for the frog with a pan head screw which fits nicely into the depression in the bottom cover plate. When you drill and tap the hole, use a little WD-40 for cutting oil, and it will drill and tap much easier. I also replaced the ground terminal because I am not adding Bob's cap discharge modification. To do this, I polished the metal tab that sticks out of the motor housing and also polished the area of the stud that would be soldered. Then I soldered the stud to the metal tab. Then here is the tricky part. I put a thumb nut onto the stud and used a pair of channel locks to hold the stud tightly into the bottom cover plate. The channel lock jaws are slightly offset so I could have one jaw on the thumb nut and the other on the bottom cover without covering up the hole where I was going to solder. Then holding the channel locks in one hand and the soldering gun in the other and having the solder draped over the edge of the table, I was able to do this 3 handed operation by myself. You can check your work by making sure the cover is held tightly by the soldered terminal. I also soldered two of the tabs that hold the outside rails in place to make a good connection between the outside rails. I had one switch that had the ground terminal broken off and it was lost. I soldered a 4-36 pan head screw to the bottom cover and made a new terminal. The thumb nut holds it tight to the metal tab coming out of the switch motor. Bruce Baker

[lionelsoni]

Yes.  It looks promising.

[Civil War]

 Bob,

Thanks for clearing that up. Here is the listing for the transformer. It says it has an 18 V DC output. Do you think this will do the job?

Transformer

[lionelsoni]

It's a good thing you posted that.  It should read, "The other side of the lamp is connected to a 16-volt (approximately) DC supply, whose positive side is returned to the outside rails."  I thought I had swapped all the "positive"s and "negative"s earlier; but I missed that one.  By the way, do you think the Tyco will put out enough voltage?  You need a good 16 volts.

You don't need diodes for the indicators if you run them from one of the DC supplies, set to 12 volts.

[Civil War]

 Bob,

 I got my SPDT momentary toggle swithces to day. I think they will work very well and are pretty small.

We have gone back and forth on the turnout modification so I just want to be sure I have it right before I start on that part of the project. Below is what I have. Let me know if this is correct.

Normal 0

Modifying the turnout:  Take off the switch-machine cover and drill out the rivets that hold the plastic top to the steel bottom.  There are two rivets on the switch machine, but only one goes through to the bottom.  The bottom of the frog is the second; and the bottom of the common terminal is the third.  Pry up the tabs that hold the outside rails to the turnout, but only enough to get the bottom plate off, since they will break easily.  Identify the two wires, one from each coil that connect to the center rail.  Unsolder them and resolder them to an insulated wire.  Insulate the solder joint.  Find or make a path for the new wire out of the turnout in a place where it will not be pinched.  Drill and tap the frog, starting at the bottom end of the post that you drilled off, for a 6-32 screw.  Go ahead and drill and tap it all the way through to the top.  Put the turnout back together, using machine screws to replace the rivets and a flathead screw to hold the frog on, just long enough to come flush with the top of the frog casting.  The common terminal is no longer needed and can be replaced by a simple screw.

The capacitive-discharge circuit is very simple (not for me).  It is an electrolytic capacitor, about 4700 or 5000 microfarads), with its positive terminal connected to the outside rails and its negative terminal connected to the new wire that you installed.  The capacitor's negative terminal is also connected to one side of a number-53 lamp.  The other side of the lamp is connected to a 16-volt (approximately) DC supply, whose positive side is returned to the outside rails.

I am getting a couple of Tyco HO transformers. They should work for the DC power source. If I have this correct I can modify my first turnout. Then I will be ready to start on the toggle switch, latching relay and diodes. I went to Radio Shack today and they only had one diode in stock but will have more on Wednesday. I will need two correct, one for each indicator light? I plan to make up a small temporary control panel to operate one turnout to make sure everything works as expected, then it will be easy to modify all the other turnouts. I'm going to take pictures and write up a step by step proceedure. Thanks for your time and help.

 

Normal 0

[Civil War]

 I got the LEDs today. They are wonderful. Very small. I will only need about a 3/16" hole in my panel for them. If anyone needs LEDs in red, green or yellow check out these:

Blue Sea Systems

[lionelsoni]

You're right about SPDT instead of SPST.  I have edited that error out.

Because we're using the capacitive discharge circuit, we must use DC to power the turnout.  All it is is the electrolytic capacitor charged to about 16 volts (or whatever it takes to throw the turnout, probably more than 12) powering the turnout coils and the latching relay coils (which will be wired in parallel with the turnout coils).  When you throw the turnout, you get voltage from the capacitor for a short time, until it discharges.  That is what protects the turnout coils from burning out.  There is no harm in giving the relay a little extra voltage for such a short time, even though it is rated at 12 volts.

You can make your own DC supply if you want from a small train transformer.  This is very simple to do and would give you the ability to adjust the voltage if you need to.  This requires a bridge rectifier and another electrolytic capacitor.  The only thing you will need 12 volts DC for is the LEDs, which will be controlled through the relay contacts; so that can be a separate HO-type power supply.

The first step will be rewiring the turnout.

[Civil War]

 Bob,

 I am rounding up the parts I need to convert one switch. 

I have

1 electrolytic capacitor about 4700 or 5000 microfarads 4700 uF 35V 20% Axial-Lead 

Normal 0 1 14.4V 120mA Incandescent Flashlight Bulb bayonet base - I also got a socket so I can change out the bulb if it burns out and so I won't have to solder directly to the bulb.

Normal 0 1 Panasonic Electric Works: Low Signal Relays - PCB 2A 12VDC SPDT 2 COIL LATCHING PCB 

1 green and 1 red LED indicator lights

I still need to locate a 12V DC power source. I like your SPDT toggle switch and diode idea better since I wouldn't need the DC power source.

You said I could  Normal 0 use an SPST (shouldn't this be a SPDT ) switch instead of DPDT, operating both the turnout and the relay with the same contacts.  You would have to put a diode (1N4001) in series with each relay coil to get the DC that it needs from the AC track voltage; and you would have to use a lower-voltage relay to compensate for the half-wave rectification Normal 0 http://www.mouser.com/Search/Refine.aspx?Keyword=DS1E-ML2-DC5V

If this is the case I would still need to get the diode and the relay I have would not be correct. I have ordered  Normal 0 SPDT Momentary-Off-Momentary TOGGLE SWITCH so it looks like I still need the diode and the lower voltage relay.

Does this sound correct?

Once I get everything I need I'll start the conversion, but I am sure I will need some additional advice on how to wire the toggle switch, diode and indicator lights. Thanks. Can't wait to get started and see this work. 

 

[lionelsoni]

(Submm) Bob, I see that I didn't answer your questions.  The answers are "yes" and "yes", but they are related.  You can modify an 1122 or 5121 just for constant voltage; but then you run the increased risk of burnout.  The capacitive-discharge circuit protects you from that; so it's a good idea to do both.

I say "increased risk", because you can also burn an unmodified turnout up if you park a train on it with the track voltage turned up.  It's just less likely that you would do so.

[Civil War]

 

I think these will work. Since I haven't built the control panel I can make sure they will work. Couple more things to round up then I can make my first one and see how it works.

[lionelsoni]

Yes, they will work fine.  You could also buy naked LEDs and add your own ballast resistors, but those will save you that trouble.  It looks like they will each occupy about a 1/4-inch-diameter circle on the panel.  Is that small enough?

[Civil War]

 

Bob, I am thinking these red and green indicator lights will work on my panel. They are 12 volt. What do you think. Sorry to keep bothering you, but once I find all the parts I can get started.

 Indicator lights

[lionelsoni]

That looks perfect.

[Civil War]

lionelsoni

I don't see any momentary SPDT toggle switches in the Radio Shack catalog. 

 

Bob,

I found this switch http://www.mpja.com/prodinfo.asp?number=5009+SW

What do you think of this one?

[Civil War]

lionelsoni

the latching relay should be the 12-volt model, not the 5-volt. 

 

Bob,

I ordered one latching relay. This is the one I ordered. Is this correct. 769-DS1E-ML2-DC12V
2A 12VDC SPDT? If not that is OK I only ordered one to try my hand at switch modification. If this all works I can do the rest. I'll be stopping at Radio Shack for the capacitor, switch, #53 lamp and the red and green LED indicator lamps.

 

[lionelsoni]

I hope you haven't ordered anything yet.  Since you're going with the DC capacitive discharge scheme, the latching relay should be the 12-volt model, not the 5-volt.  And, because it is a polarized relay, the positive side of the capacitor should be connected to the outside rails, not the negative.  Although they don't call it by that name, you can get the number-53 lamp (and sockets for it) at Radio Shack:  http://www.radioshack.com/product/index.jsp?productId=2103782  Note that we are not using the lamp as an indicator, but as a resistor to charge the capacitor.  I don't see any momentary SPDT toggle switches in the Radio Shack catalog.  They do carry this DPDT:  http://www.radioshack.com/product/index.jsp?productId=2062530&filterName=Type&filterValue=DPDT  I think a miniature switch would be a better fit for your panel; but you'll have to order that.

[submmbob]

 Bob

Remind me what the advantage of the capacitive discharge setup. Is it just so the switch can be thrown w/o track power or also to prevent switch burnout if a train is parked on it?

Bob

 

 

[Civil War]

balidas

If you would post pix of your progress. I think I might pull apart one of my turnouts also.

 

 

Will do. I'll post step by step pictures. 

 

[balidas]

If you would post pix of your progress. I think I might pull apart one of my turnouts also.