# A/F 15B Transformer Question



## AFOkie (Mar 31, 2018)

My wife inherited her Father's train collection and I am going through the pieces to determine what works and what needs so TCL. The A/F engines and transformers have been sitting in boxes for the past 20 years so they need some TLC. I did not grow up with trains so this is a new world.

I am currently going through the various transformers. When I test the 15B it doesn't act like I would expect. I am attached to the Base and 5-16V connectors. When I lift the deadman I still have 5V showing on my meter. I have a 16B and when I lift the deadman the meter show 0V. I have cleaned the 15B and the carbon wheel seems to operate fine. 

What should I look for to determine why there is still voltage when the deadman is lifted? 

Thanks
Ron


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## BrokeCurmudgeon (Feb 8, 2016)

AFOkie said:


> My wife inherited her Father's train collection and I am going through the pieces to determine what works and what needs so TCL. The A/F engines and transformers have been sitting in boxes for the past 20 years so they need some TLC. I did not grow up with trains so this is a new world.
> 
> I am currently going through the various transformers. When I test the 15B it doesn't act like I would expect. I am attached to the Base and 5-16V connectors. When I lift the deadman I still have 5V showing on my meter. I have a 16B and when I lift the deadman the meter show 0V. I have cleaned the 15B and the carbon wheel seems to operate fine.
> 
> ...


I have a 15B also. I will go out to my layout and measure the voltage with the dead man lifted. I don't think that there should be voltage there but who knows in the world of AF. We will see...


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## BrokeCurmudgeon (Feb 8, 2016)

I checked my 15B and it reads 0 volts when the dead man is up.


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## cramden (Oct 13, 2015)

When you lift up the handle, underneath is a spring loaded stud sticking up that the arm presses down on when its held down or in the clip. That spring loaded stud pops up and cuts the power to the circuit. You should be able to press it down with a small flat blade screwdriver or needle nose pliers. If it's already down then the spring is broken or has lost it's strength. It's possible that it might be stuck down, try spraying a little electrical contact spray on the post and see if it frees it up. If the transformer has been stored for a long time with the handle clipped down, the spring may be bad. I don't think the contact lever and stud assembly has any serviceable parts. Here is an exploded view of the transformer, it's comprised of 4 pages. Click on the arrows at the top to turn the pages. Hope this helps.http://myflyertrains.org/gallery/album211/15B_1


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## AFOkie (Mar 31, 2018)

I'll do some more tinkering. It reads 5V which the deadman up no matter where the wheel would be across the coil. Thanks for the help.


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## cramden (Oct 13, 2015)

AFOkie said:


> I'll do some more tinkering. It reads 5V which the deadman up no matter where the wheel would be across the coil. Thanks for the help.


Did you see if the stud is up when the arm is up? Even with the dial set to 0 volts it will still show around 5 volts because the transformer is designed to keep that amount so if you stop the engine the reverse unit has enough volts to keep it from cycling into neutral. If the stud is down the variable post will still have 5 volts.


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## AFOkie (Mar 31, 2018)

Yes the stud assembly rises and I can push it back down. When pushing down I can feel the spring tension. If the unit is to keep 5V on the reverse unit then it is working correctly?


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## cramden (Oct 13, 2015)

AFOkie said:


> Yes the stud assembly rises and I can push it back down. When pushing down I can feel the spring tension. If the unit is to keep 5V on the reverse unit then it is working correctly?


Yes, it's working as designed. The voltage might not be exactly 5 volts but it will be somewhere around 3.5 to 5 volts. As long as the handle keeps the plunger down you will get that residual voltage to the variable post.


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