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American Flyer Reverse Unit Issues

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  • Member since
    December 2016
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American Flyer Reverse Unit Issues
Posted by JeepGuy25 on Friday, December 9, 2016 12:32 PM

Hi everybody!  My name is Justin.  First post here.  I have a bunch of hobbies...model trains isnt one of them at this time haha.  I love them, but dont have the space, and haven't really messed with them since I was little.  My dad has his dad's American Flyer 295 (1951), and Im fixing it up for him.  It was a wiring mess, needs a new smoke wick, and a good cleaning.  

I got a new wiring harness, and have the tender all wired up.  The major issue is, the unit will only switch when it wants to.  Everything mechanically works perfect.  Smooth, clean, oiled.  It just seems like sometimes the coil wont move the flapper.  Like it doesnt even try.  If you lightly tap the top of the reverse unit, it will switch.  And it also seems like it takes a LOT of transformer voltage to make it switch.  You have to really crank it.  

Is this something I can fix?  It seems like the coil itself has an issue.  I touched up the solder joints for the coil thinking maybe a poor connection.  It will work maybe 20 times in a row perfect, then will hardly switch at all without tapping it.  

Does anyone know what the resistance reading on that coil should be??

Thanks in advance!  Looking forward to checking out the community and participating as much as I can!

 

Justin

  • Member since
    November 2015
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Posted by Sturgeon-Phish on Saturday, December 10, 2016 7:36 AM

Justin,

Welcome to the CTT train forum

The AF Reverse units are finicky.  When you cycle the power, do you hear the solenoid click?  If so you’ve got power to it.  As it cycles or attempts to cycle watch the right hand side of the unit and see if each solenoid cycle advances the drum incrementally.  Did you replace or clean the fingers that contact the drum?

From here and usually what is going on after a drum cleaning the fingers are not making contact with the drum, or make too much contact.  If no contact slightly bend the fingers down to the drum.  If they are in contact pull up on them slightly to decrease the pressure of the fingers on the drum, as that can prevent the drum from rotating.

 

If cycling the unit and the drum doesn’t rotate, look closely at the little brass colored pawl.  With each cycle it should move to rotate the drum.  If it doesn’t there are a couple of things I’ve done to fix it.  First reclean and lube and then if that doesn't work, CAREFULLY and SLIGHTLY bend the exposed part of the pawl away from the frame.  With use the pawl can wear a notch in the frame and make it harder to move.

 

Lastly expose the coil and remove the core.  If it is rusty polish it with emory cloth and clean the unit with a good electrical cleaner / lube and reassemble.

Let us know how you’re coming with this

 

Jim

  • Member since
    September 2004
  • From: Dearborn Station
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Posted by richhotrain on Saturday, December 10, 2016 7:46 AM

Justin, you just got a lot of great advice from Jim. 

Let me add one point (which I learned from Jim a few years back). On these old locomotives, the fingers that contact the drum have small spoon-shaped ends. Over time and repeated use, the spoon can literally wear a hole in itself so that the point of contact is too limited to work properly. Check that out as well.

Rich

Alton Junction

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Posted by lionelsoni on Saturday, December 10, 2016 9:09 AM

I measure 18 ohms.

It is possible to get a second life out of reversing unit (and e-unit) fingers when they wear out.  They normally end in a semicircular arc, with a sharp 90-degree bend where the arc joins the straight part of the finger.  When the semicircular arc wears through in the middle, just flatten the 90-degree bend to about 45 degrees, thus moving the point where the (shortened) arc touches the drum to a new, unworn spot.

However, if you can't get the armature even to move, refurbishing the fingers won't help.  (By the way, e-units have solenoids, but Flyer units just have a plain electromagnet.)

Bob Nelson

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  • From: Dearborn Station
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Posted by richhotrain on Saturday, December 10, 2016 10:34 AM

lionelsoni

It is possible to get a second life out of reversing unit (and e-unit) fingers when they wear out.  They normally end in a semicircular arc, with a sharp 90-degree bend where the arc joins the straight part of the finger.  When the semicircular arc wears through in the middle, just flatten the 90-degree bend to about 45 degrees, thus moving the point where the (shortened) arc touches the drum to a new, unworn spot.

Good description, Bob.  That semicircular arc is the "spoon" that I referred to in my earlier reply.

Rich

Alton Junction

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Posted by JeepGuy25 on Sunday, December 11, 2016 12:16 PM

Hi everyone.  Thanks for the welcome and AWESOME responses!! 

Now that we have a starting point, I will try to detail a little better what Ive done to the train so far.  

Ive completely disassembled the tender, including pulling the drum.  I cleaned all mechanical linkage, and lubed.  I cleaned the drum and its nice and shiny.  I replaced both finger boards, because a previous "tech" fabricated one of the fingers out of copper sheet and it was a mess.  All fingers are making contact, but not too much.

When operating the flapper manually, by the little locking tab on the back, the drum rotates freely every single time.  Its smooth, and seems easy to activate.  

I have replaced the entire harness with a repro as my pins on the jack panel were REALLY mangled.  Again from previous "tech"... I installed new brushes and springs in the engine since one side didnt even have a spring, and tested.  The train functions in both directions, no problem.

So...the tender will switch on its own.  When the coil energizes and the flapper pulls up, it will work great.  But occasionally, and more frequently now, the flapper wont even attempt to move.  I measure 15.8 ohms across the coil.  When the unit does work, I feel like it needs more power than some Ive seen online.  I have to really crank the transformer.  Then it will move.  When it doesnt work, it doesnt even seem like it attempts to move the flapper or the paw.  If you leave power on, and give the unit a light tap, it will move the flapper and advance the drum.  I remember as a kid my dad having to tap the tender to make it switch direction...so this has been an issue with it for quite some time.  

When I found this forum, I was really trying to hunt down any information on refurbing the coil itself, if its possible.  After reading the responses here, it sounds like I might be able to.  I want to clean the area between the coil and flapper, because I think there is rust or corrsion there.  Is my resistance reading within spec? I imagine if worse came to worse, I could get some winding wire and rewind the sucker...its just a simple electromagnet.  

I know those units can be a pain.  Ive seen some operate like clockwork though since starting this project.  If worst comes to worst, Ill lock it in forward, finish refrubing the engine, and deal with the tender later.  Or switch to an electric unit.  Engine needs cleaning, full lube, new smoke wick and element, and I think it needs a new light bulb.  She'll be ready for some laps around the tree at least! 

Thanks again for the advice!  

 

Justin

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    November 2015
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Posted by Sturgeon-Phish on Sunday, December 11, 2016 12:43 PM

Justin,

It sounds like you are eliminating some of the most frequent problems.  Look at the opening where the pawl comes through the side frame and see if there a notch worn into the frame.  I’ve not seen it often but a well used reversing can wear a notch that the advancing lever hits.  Take a small round file and polish the edges, and while apart look at the advancing lever to make sure it’s not binding.  

If you apply power to the reversing unit directly does it work, then act up when applying power via the wheel set?  If so clean the conductor wheels and make sure the metal strip that rides on the axle is applying pressure to the axle.

 

Also remember the unit has to be right side up so the weight of the flapper will let the drum completely cycle.  

 
If all else fails and you want to get it going, switch to DC operation and like you said lock in the unit.
 

Keep up the good work and let us know what works

 

Jim

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Posted by JeepGuy25 on Sunday, December 11, 2016 12:45 PM

Not sure if I can use IMG tags here...but here is a quick shot of the reverse unit.  Just to show that its not totally clapped out and that Im not putting it together with duct tape and bailing wire...which certainly comes in handy on some of my projects haha.  The green wire will be replaced before I button it up, it was heavier gauge than I thought and once I soldered it in, I realized it was WAY overkill.  

 

If the IMG doesnt work here is a link:

http://i57.photobucket.com/albums/g221/jeepguy25/MISC/20161211_130947_zpshdo6i9gf.jpg

Justin

  • Member since
    December 2016
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Posted by JeepGuy25 on Sunday, December 11, 2016 12:51 PM

Thanks again Jim.  I didnt notice the notching that happens on some of them, it seems to be nice and clean.  Also no binding.  

One thing I didnt try was powering the coil direction.  Thats brillant.  Im just assuming power is coming through the trucks as it seemed to be working for a bit.  I will clean things up some more, maybe take some tension out of the fingers, check for the notch again, and try applying power directly to the coil.  If it operates consistently, I will focus on the wheels, axle contacts etc.  I did clean then...but only a quick job when I first started the project.  

Im hoping to work on it tonight some.  I still have a lot of work to do on the engine, and I still want to clean up enough track to make a circle, and maybe build a platform for it.  I have lots of cars, so Im going to pick 3 or 4 of the best including the caboose and clean those up as well.  Ide like to make a modular platform that could be taken apart into 4 pieces or something.  Just something to set up quickly for under the tree.  It will totally make my dad's Christmas if its running.  Especially when he can share it with his grandson.  So Im pushing to get her done!

Justin

  • Member since
    December 2001
  • From: Austin, TX
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Posted by lionelsoni on Sunday, December 11, 2016 5:49 PM

The fact that your resistance measurement is a little lower than I got makes me wonder whether you have some shorted turns in the coil.  Shorted turns might have a modest effect on the resistance, but can be devastating for AC operation.  If you have a DC source (9-volt battery?), try that on the e-unit coil and, if it works a lot better on DC, that might be the answer.  Unfortunately, the fix is to rewind the coil.

Bob Nelson

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    November 2015
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Posted by Sturgeon-Phish on Sunday, December 11, 2016 6:44 PM

Another alternative is to get a coil from other source, maybe an uncoupler as I belive they are the same coil.

Jim

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    December 2016
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Posted by JeepGuy25 on Monday, December 12, 2016 7:05 AM

I think I got it nailed!!!  After talking to you guys, I started to think about it more.  I was getting power to the coil even when nothing was happening.  And I knew if I tapped it, it would work.  I couldnt think what tapping would do to make a coil work.  So when it would stick, I would very gently help the flapper along, and with the slightest touch it would snap up to the coil.  Then I moved the locking lever a tiny bit, to sort of bring the flapper closer to the coil, and viola!  

I have a theory.  It works great for 20 cycles when you first fire it up, then seems to not function very well.  I think the flapper is getting magnetized, and is touching the tender chassis and sticking.  Keeping it away from the tender chassis a tiny bit lets the coil pull it up easier.  Here are a couple of pictures to show what I did.  There is a tab on the front end of the reverse unit, and I bent it up a bit to keep the flapper from touching bottom.  It works 100% of the time now and very very smooth.  WAY less voltage required to get it moving.  

Before:

After.  The tab is right behind the front most screw for the reverse unit:

After that I got everything back together and cleaned up.  Put in the new smoke wick, gave everything some grease and oil.  MAN...she runs so quiet now!  I never remember it running that quiet.  All I need to do is get the couplers moving more freely, clean up the cars, replace some light bulbs and figure out what Im doing for a track layout.  

Here are a couple more pictures just for the heck of it.  Thanks again for the help on this!  These forums are great!

What I started with:

Here you can see the old vs new finger boards.  You can see the one finger on the top board that someone fabricated on their own.  

Ready to go:

And just a shot of the ol' girl before cleaning.  She's a little beat up.  But runs smooth and quiet now.  We'll see how she goes around the track.

 

Thanks again!

Justin

  • Member since
    January 2024
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Posted by PB53 on Wednesday, January 10, 2024 7:07 PM

How do you remove the AF core from the coil? From what I can tell it seems to be permanently installed - thank you

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Posted by Laurastom on Thursday, January 11, 2024 4:13 PM

Excellent work! Just for future reference, the 295 uses an XA10587 reverse unit. The coil is an XA9800-A. That coil should measure 14.7 to 15.7 DC ohms. That resistance range applies to all the early Gilbert reverse units beginning in 1946. When Gilbert changed some engines to the motor mounted reverse units in 1955 and later, the new coil design for those reverse units measures 26 to 32 DC ohms.

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