Help diagnosing a sluggish O-22 switch problem

[Birds]

One of the O-22 switches I received a couple months ago is acting sluggish with 15 volts of constant voltage going to it. The other 5 switches have a good snap to them. I thought running it and working it might loosen it up, but it hasn't made a difference.

I took the cover off of the switch mechenism and noticed that the brown wire which is soldered to the middle section of the terminal plate assembly, the plate the constant voltage pin is soldered to, (item 40 on the Lionel exploded diagram) was caught between the housing for the switch cover and the metal base and the wire has been squished flat.

Would this brown center wire being squished flat be a possible cause for the switch not having a good snap?

What have been people's experiences with things like this when brought to a repair center? Are the sent out, repaired on site, exchange right away?

Thanks,
Birds

[waltrapp]

"Would this brown center wire being squished flat be a possible cause for the switch not having a good snap" - are you sure that it's not more than just "squished"? Can you conduct a conductivity test?

The only other thing that I've experienced that makes them sluggish is a dirty (can't think of the word to describe the part that I'm thinking of - the metal rod that slide back and forth "inside" the coils).

- walt

[Jumijo]

I was just reading about switch maintenance last night. Clean the mechanism well and apply a small bit of grease to the gear. Re-assemble the switch and make sure nothing is binding or too tight. If that brown wire's insulation is exposed, cover it with electrical tape.

Does that brown wire get hot with operation?

Jim

[Birds]

Thanks for the replies.

I will check to see if the brown wire gets hot.

This switch is only three months old. It is well lubricated and there is no dirt inside. I initially took the cover off to see if it needed cleaning and it looks great.


The only other possibility that I could come up with is that somehow I weakened the solenoid.

At one point with a layout design I tried to setup automatic switching using an isolated outside rail as a knife switch. I found the trains could end up in a situation where they would cause the switch to be thrown both ways at the same time. The result was that the solenoid was "chattering" trying to do both. Or it would throw one way and immediately throw the other. I changed the setup as soon as I realized what was taking place, but I wonder if all that somehow weakened this particular solenoid.

[fwright]

You can't really "weaken" a solenoid. What can happen is that the coils have current flowing through them for too long a period of time, and overheat. If they overheat to the point that the wire insulation melts, then adjacent wires in the coil can short across to each other or to the frame. If adjacent wires short to each other in a couple of places, then the magnetic field produced by the coil is reduced, you hold the control on longer to get the switch to throw, and the coil takes more current, thereby heating up even faster, which can cause more insulation to melt, and so on.

Actually, the above is fairly rare because an overheated solenoid will usually end up as a complete short or open. Usually a solenoid either works or doesn't work. And if it is electrically sound, the problem is almost always a mechanical binding or hitch in the mechanism.

To check the solenoid, measure the resistance of some solenoids on some good switches, and compare with the coil resistance of the solenoid on your problem switch. If the resistance of the problem switch solenoid is significantly lower than the others then you have internal shorting.

Have you tried the problem switch with a higher voltage? If you get snappier action with 18 volts, that points to a stiff or binding mechanism.

Hope this helps
Fred W

[Roger Bielen]

With a car parked on the switch causing the selonoid to overheat I've warped a selonoid just enough for the rod to bind. Check that the rod slides in and out or the selonoid without problem. Also check that none of the other moving parts are binding.

[Dave Farquhar]

I had a sluggish switch once that just turned out to be poor solder joints. I touched up the solder joints, and then it worked as well as my others.

[lionelsoni]

A good way to check the coil against a good switch is to wire their coils in series. Then put voltage across the combination from your transformer--briefly! The voltage at the midpoint should be half the total voltage.

The advantage of this method is that a test with AC is much more sensitive to shorted turns than DC. If one of 100 turns is shorted, the resistance will be reduced only 1 percent, far too little to see with an ohmmeter. On the other hand, a single shorted turn will greatly reduce the AC impedance of the coil, which is mostly inductive, and unbalance the series circuit that you have created for the test.

[Birds]

Thanks for all the tips!

I think I fixed the problem. I went back and looked over the linkages and parts again with a focus on things that might bind. That was less invasive to start with than getting into the wiring tests. The problem appears to have been a binding issue.

The metal frame (part 5132-213) that goes over the solenoid has a tab on it which holds the locking bar. This tab was bent inwards enough so that the locking bar was being hit by part of the plastic lantern retainer every time the retainer rotated towards the side with the voltage plug. A wear spot was beginning to develop on the lantern retainer where the two came in contact. I gently bent the tab out on the solenoid frame, and the lantern retainer is free to rotate. The snap appears to be equally solid in both directions now.

I inspected the solenoid and it looks to be in good shape. The plunger also slides freely. However, I did notice that brass part of the plunger (the part that connects to the rack and pinion plate) had a slight bend in it.

I greatly appreciate all the tips on how to test the electrical components. It is good information to keep on file.

One interesting thing I discovered. I have some new O-22 switches, and some of the 5132 & 5133 switches from the early 1990s. The new O-22 switches have screws everywhere and you can take the entire switch motor unit apart and replace parts if needed. It is easy to work on.

The 5132 & 5133 switches from the early 1990s have parts riveted together, so you are limited in what you can take apart. For example the frame covering the solenoid appears to be riveted to the base on the 5132 & 5133 switches. It is screwed to the base on the new O-22 switches. It would take more work to replace the solenoid on the 5132 & 5133 switches compared to the new O-22 switch.

Thanks again,
Birds