Buzzing in Lionel 1121 and 1122 switches (027 gauge)

Niño, I believe there is a way to power the switch with DC, or using a bridge rectifier that will cut the noise.  I had learned this many years ago and don't recall the specifics, but I think it is a relatively easy fix.  Good luck, dennis

Nino,

  The buzzing of the coils is normal, and happens exactly as you state due to the non-derailing feature of the switches. Powering the switch coils with DC will quiet them down.

Larry

It will also eliminate any warning that a coil is overheating, when you park a train on the turnout.  You need to put a capacitive-discharge circuit between the DC power supply and the turnout.  It can be very simple, just an electrolytic capacitor and an incandescent lamp.

Bob,

About a year ago, I converted my 1122 switches to fixed voltage. I didn't use Lionel's method of trying to grab the coil wires under the solenoid. I simply Dremeled a window into the bottom of my switches and added the jumper right there. Works great. I also added knife switches to cut the power to my two blocks of switches to eliminate buzzing if trains are parked on them. By the way.....I discovered that this also eliminates the sudden stops that MTH engines do when passing over PW switches. Recently, I replaced my 027 switch controllers with 022 controllers and added a nice toggle setup to allow the lamps to show the proper position. 

About a week ago, I decided to try and eliminate the solenoid buzz completely. I found one of your posts on a Forum and got the components and wired it up. It didn't work. No matter what I seem to try, I've had no luck. I thought perhaps the components were bad and I swapped them out. I'm not getting enough power to either light the lamps (they stay VERY dim) and the switches won't switch.My wiring setup for fixed voltage works fine, but as soon as I add the capacitor, resistor and diode.....nothing. Do you have any ideas as to what the problem is and perhaps a solution for it?  I've spent many days now on this and I'm stumped.

Thanks,

RogerNY

RogerNY  - Welcome to trains.com!

If you just added the capacitor and lamp to your existing setup, then the problem probably is that you're still using AC.  You need to use a DC supply, returned to the outside rails (or a transformer terminal  connected to them) and with its polarity matching the capacitors.  For example, if the negative terminal of the power supply is connected to the outside rails, then the negative terminals of all the capacitors should also be connected to the outside rails..

If you did put in a DC supply, check to see whether the capacitor and supply polarities match.

Hi Bob,

Thanks for the response. I'm a bit confused, though. I do not have the thread about using a lamp and a capacitor. I am using the diode, resistor and capacitor. I've got my fixed voltage switches hooked to my ZW, although to test out the three components I also used a separate AC transformer. Do I need a DC transformer? I thought the diode changes the current to AC?  Shoud I bag the three components I used and try something else? What's the best way to do this? Thank you.

Roger

Bob, it may also be that Roger has it wired such that the lamp on the controller is a load on the capacitor in which case the lamp charging the capacitor and the lamp on the controller are acting as a voltage divider and the cap is never charging up to the necessary voltage to operate the switches.  

Servoguy,

I think you may be on to something here. I've kind of suspected that the 022 controllers might be playing a role in this. I'm going to go downstairs and remove a bulb from it and see what happens.  The strange thing is.....the system works perfectly until I put those 3 components in.....then nothing (or barely). I'll get back to you on this.  If that is indeed the case......smaller resistor?  But I'm getting ahead of myself.

Roger

Nope.....still no dice. However, something interesting.....I took the wire to ground (to the switch ground terminal) off the cathode side of the capacitor and tried it on the other side. Pushed the switch controller lever and got a "click" but that's it. Something is not quite right here.

Roger

Maybe you can detect the problem in my setup. Ordinarily, I have my fixed voltage switches connected to the B terminal on my ZW. But to test all this stuff, I've been using a separate small transformer. I have the + terminal of the trans. connected to the jumper coming off the switch. The common of the transformer I've got clipped to an outside rail. And everything works with that....switches work, controller bulbs light up. Now, when I add the diode, resistor and then capacitor to that circuit.....nothing. ??    

Here's another alternative I want to run by you folks. What about using a separate DC transformer (instead of my AC ones)? Wouldn't that eliminate the need for the diode, resistor and capacitor?   Or would there be a problem with it mixing with the AC at the switch (ground terminal on the switch) where the controller wires come in? 

Roger

Guys,

The problem IS the bulb. I played with my connections again and unscrewed the bulb. The switch "snapped" for the first time. Finally some progress. But.....when I screwed the bulb back in, it was initially bright and within seconds it dimmed to almost off (and of course, the switch didn't work anymore). So....I think we've found the problem. Now.....as to a solution?   I'm thinking that the resistor is too large for the switch AND a bulb (as Servoguy suggested). How do we calculate the size of the needed resistor? I kind of had a feeling about that last night and tried something extreme......I removed the resistor completely and then within seconds, there was a nasty smell. That was a microsecond before the diode exploded.

The two bulbs in the controller are 18V screw in. However, because of the mod I did on the controller, only one bulb is on at a time. Normally, as you know, 022 controllers with 027 switches will work the switch, but both bulbs stay on. 

Roger

Roger, the resistor (or light bulb) that charges the capacitor does not supply enough current to light the the light bulb in the controller.  That is the whole idea.  The resistor limits the current through the coils to keep them from emitting smoke.  If you changed the resistor so that the capacitor voltage stays high enough to light the bulb in the controller, it would also be high enough to smoke the coils.  

Exactly right.

I think you found an old post describing an early version of my circuit.  If you use a number-53 lamp instead of the resistor and power the whole thing with a DC supply, it will work much better, with a much faster recharge, while still protecting the turnout.

Bob,

Just as I thought...the bulb.   So, let me get this straight then.....you suggest that I keep the diode, put it in line with a #53 bulb and then the capacitor, but instead of my ZW for power, use a DC transformer? Is that all correct?        And I have one more question if it is.......if I'm going to power the switches and controller bulbs from a DC transformer, why the need for the diode, lamp and capacitor? 

You folks are being real helpful and I appreciate it. Thanks!

What is the link to the post that includes the bulb as a substitute for the resistor?

Roger

No need for the diode with a DC supply.  Connect the negative terminal of the DC supply and the negative terminal of the capacitor to the outside rails.  Connect the positive terminal of the DC supply to one terminal of the lamp.  Connect the other terminal of the lamp to the positive terminal of the capacitor and to the common of the solenoids.

If you want to make your own DC supply from the ZW, connect the anode of the diode (1 ampere, 50 volts minimum, a 1N4001 for example) to a ZW output terminal.  Connect the cathode of the diode (the end with a ring painted around it) to the positive terminal of another electrolytic capacitor (2200 microfarads, 16 volts minimum) and to the lamps of all the capacitive-discharge circuits you have.  Connect the negative terminal of the capacitor to the outside rails.

You might want to read this recent topic:  http://cs.trains.com/TRCCS/forums/t/202264.aspx

Hi Bob,

But here's the crux of the problem.....I replaced the 1122 controllers because they have a silly design and you really can't see the bulb colors. Then I had to modify my 022 controllers with a toggle and DPDT switch so I could show just green or just red (to correspond with switch position). And it all works great. So.....if this buzz fix doesn't allow power to the controller bulbs, it's for naught. I have to figure out a way to to provide separate power to those controller lamps so they'll still get power and .....work with my toggles. 

Thanks!

-Roger

The only way I can see it working with your present scheme is to put smaller lamps into the 022C, such as number 52s, and then use a larger lamp, like a number 57, to charge the capacitor.  This would keep the steady-state current through the coils about the same as it is now, which is safe.  You would probably have to color the 52s yourself and they wouldn't quite fill up the holes in the 022C (G-3.5 versus G-4.5).

Otherwise, you could modify the 022Cs for separate power to the lamps.

Bob,

Well, I had some success earler this afternoon. I have 4 wires coming off my DPDT toggles to the lamps. One wire connects to the side of a lamp, the other to the contact pt. to the nearest switch wire. I had cut a slit in the connection between the lamps and the rest of the switch controller. That's why my toggles can work the lamps. I have MPC and modern controllers with jewel caps so I don't have to worry about bulb color (my parts guy provided me with caps that are color matched). Anyway......this afternoon, I removed one lamp wire each....the one that connects to the switch wire contact pt inside the controller. I then clipped one wire each from the contact points of my open knife switches and connected each to the open lamp wires. Bingo! My toggle works the lamps and the capacitor, diode, resistor is switching the switch. Very cool. When I clean it up ( and make sure it's REALLY working) I won't hook to the knife switches....that was just a convenient short wire's length. I'll probably create terminal blocks from the ZW output I use for this.  So far, so good. Finally some progress. Seeing the switch swivel and the lamps lighting WITHOUT buzz is pretty exciting. 

You and Servoguy have been real helpful. I may yet be back to you, but so far, I'm liking what I'm seeing (and not hearing).

Roger

You mentioned the diode.  Did you use it to make a DC supply, or is it in series with the lamp?  The latter will work, but the recharge time will be longer.

Bob,

I ended up with the original setup......power from ZW to diode (1n4001) to 100W resistor to 4700uF capacitor . The anode end of the capacitor also has the jumper wire from the switch attached there and the other end is attached to the ground terminal on the switch. Wonderful!  The switch "snaps" nicely....I get about 2 fast switches per charge (more than enough) and the controller lamps work great.     If I decide to do the lamp "resistor" rather than the ceramic one, I could do that down the line. In fact, I was just ordering the parts for my other 7 switches. These won't be from Radio Shack. Mouser or Digikey...much cheaper.

Now, why wouldn't a straight DC transformer by itself (without the other 3 items) do the trick?  I did try a 6 amp diode by itself before and it worked, but there was bad buzz, so I suspect the same would occur with a DC transformer by itself. Would you agree with that?

I'm impressed with this and very pleased.

Roger

100 watt resistor?

Straight DC would indeed quiet the turnout.  The problem with having either AC or DC powering the turnout all the time is that it is easy to burn out a coil by parking a train on a control rail.  Lionel's design of the 1122 (and its descendants) is flawed, in that they added the non-derailing feature without the internal switch that the 022 has to turn off the coil (and incidentally provide the red-green indication to the controller).  Their solution, which you can see is inadequate, was to build the turnout so that you cannot power it externally.  That way, it was less likely that a train would stop on the turnout with power still available to throw the turnout--but not certain, since a locomotive in neutral or cars not in a train can still ruin a turnout.  With external AC power, at least you have that annoying buzz to alert you to the danger.  With DC, the turnout will just silently burn up.

So, capacitive discharge is a good thing to have as an alternative to AC power, and a really good thing to have as an alternative to straight DC power.

Bob,

That's exactly what I wanted to know. In fact, when I ordered the parts for the other switches last night, I decided to do it right and do it with the lamps. So, it should work even better than it does now, which I'm actually very happy with. 

You are a great asset to this Forum. Thanks!

Bob,

While I'm waitng for the components for my other switches to arrive, I swapped out the resistor for the 53 lamp on the switch I've completed. I have a question about it. It works fine (although I did expect to see the bulb illuminated....it's mounted under the board) but what is the advantage of using the bulb rather than the resistor?  The switch snaps nicely using both.    

Another benefit from separating the controller lamps from the switch circuit. The lamps no longer blink as a train goes over a switch and do not go out if a train is parked over it. I'm liking this more and more. 

Roger

The lamp charges the capacitor faster than the (100-ohm) resistor.  The current through the coil while the controller contact is closed or while the train is on the control rail is about the same.  But, as the capacitor charges, the current drops.  The closer the capacitor gets to full charge, the slower the charging becomes.  The resistor's resistance is the same throughout; but the lamp's resistance goes down significantly as it dims.  So the lamp brings the capacitor to a full charge more quickly.

Once the capacitor is fully charged, the turnout action is the same.  It's just a matter of how soon you can throw it again.

Bob,

Ok, I had the feeling it was faster. Snap was the same, but it seemed like is was "ready to go" sooner and you verified it. I just wired up all the lamps in my controllers for separate voltage while I'm waiting for my capacitor components.

Should the lamp be illuminated at all? The one that I did is under the table. After I hooked it up, I didn't think the system was on because the lamp was not lit. Normal?

Roger

It lights when you throw the turnout and then dims out in a second or two while it is charging the capacitor.  I like to use lights around the layout, like those in lighted bumpers and billboards.  As the trains cross the control rails on the turnouts, these will light up, seemingly at random.  For a bumper, I just install a very short piece of track at the end of a siding, but completely isolated from the siding rails, then make my connections to the rails of that short piece.

Bob,

You're right! I guess I didn't have it powered up when I first connected it and because it's under the layout, I didn't see it. But.....just looked under the table and hit the lever. Bingo.  I like your ideas for putting those lamps to good use on the layout. 

Roger