022/711 Switch operation pblms

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  • Member since
    July 2009
  • 951 posts
Posted by servoguy on Thursday, March 21, 2013 2:01 PM

I recently bought some more 022 switches, and when I serviced them, I learned a few new things.

The circuit board that carries the sliding contacts sometimes will rotate causing the sliding contacts to get out of alignment.  I fixed this by putting two drops of solder on the metal slider that carries this circuit board.  Get the solder close to the circuit board.

I now recommend using motor oil on the sliding contacts after cleaning them.

Some of the sliding contacts were rotating relative to the circuit board they are mounted on.  I soldered these to the rivet that holds them, and as long as the rivet doesn't turn, the contact stays in alignment.

I discovered that the sliding contacts are sometimes made incorrectly.  The fixed contact should be raised above the circuit board that holds it so the moving contact is not lifted off of the fixed contact by the circuit board.  If the circuit board lifts the moving contact off of the fixed contact before the switch is near full throw (points incontact with the outside rail), then the points may not be close enough to the fixed rail to prevent derailing the engine.  I fixed this problem by grinding a shallow groove in the circuit board with a drum sander on a Dremel tool.  Check when you are done grinding that there is no small piece of circuit board remaining near the fixed contact.  If there is, take a small screw driver and chip it away.  After you are done with this modification, use a meter across the solder tabs of the fixed contacts to check operation.  The meter should show continuity until the sliding contacts are off the end of the fixed contacts.  When you put the switch back together, put a jumper from the center terminal to either one of the outside terminals and power the switch.  Turn the lantern until you feel the motor come on.  See how far the points are from the outside rail.  They should be no more than 1/8 inch from the outside rail.  Closer is better.  Check both directions.  This modification has made my switch operation absolutely flawless.  And this is using steamers which always had a problem with these switches due to the low contact force of the pony trucks.  The diesels always worked better because the wheels have a relatively high contact force.

I recommend you grind a groove at both ends of the fixed contact. 

This modification is going to add some time to the rework process, but it sure does make the switches work well.  I have 5 done so far, and 96 to go.  No sweat.

  • Member since
    December 2016
  • 17 posts
Posted by trains4fun on Tuesday, August 23, 2022 4:04 PM

I had an O22 that would not throw one direction.  When I purchased it, ALL these steps had been done very well. It didn't last long.    I narrowed it down to the sliding contacts.   It had continuity problems in the sliding switch.  There are 2 contact designs. Ones with tall contacts and switches that only have a small dot of contact material.  It took a lot of spring tension added to the contact arms to get the small contact version to work reliably.  

I got an older spare switch motor.  The first thing I noticed on the sliding switches was there was about 1/8" of contact brush under the arms.  They are riveted into the contact arms.  Cleaned up this motor and everything works with little adjustment.  This was a motor with the screw in bulb and cast metal lantern holder.  

The long metal contact bar for the non derailing contact in the switch housing normally has a paper insulator where it croses over the switch motor.  Mine was gone.  I found an old greeting card for the right thickness of material.  I cut a piece to fit.  Cut T slits in both ends and then carefully position the card stock ends made by the slits under the metal strip to hold it in place.  If you cut the T slits too wide, they wont have enough strength to hold it on.  

The replacement motor had the lantern housing bent so much it dragged in the hole cut for it.   I very carefully held the side of the lantern holder near the base or gears with needle nose pliers and used constant pressure for 20-30 seconds to bend it enough to clear.   Be ready to replace it if it breaks instead.  

I followed the listed steps in preping the replacement motor.  I used a Rush-Eraser to clean contact areas.  Only a little work is needed with this to clear corrosion or an oxide layer.

I used a tiny amount of No-Ox-Id contact grease on the main ground, 2 no-derail contacts, the center rail contact and the 4 sliding contacts. 4 of these are the electrical contacts made when the motor is attached to the switch.   Tiny means a small dab on a Q tip.  Then use the Q tip to treat all the contact surfaces.  This should keep the oxidation down and allow use for years. 

I use LED bulbs and have no problem with heat.  

Details on maintaining switches with pictures.

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