Lionel 1035 Transformer - A Post Voltage

[OGauge_South]

Hi… I have a Lionel 1035 Transformer from the year 1947. It is a 60 Watt transformer for single train operation. There are 3 Posts: A; B; U

The B-U Voltage Range is 8.5V- 15 Volts and works perfectly with train operation. It also measures correct voltage on the multi-meter.

The A-U Voltage Range is stated to be 13.5V - 20 Volts, but does not work. It measures 5 Volts with a Multimeter.

I looked inside and the solder joints look solid. However, in looking at the wiring, I see the U common post and B - Post are both connected to the roller arm that moves across the armature. The A-Post is only wired to the armature on the bottom.

I am wondering how the A-U post can possibly make a full circuit with variable voltage without a connection to the roller arm??

Also why would the bottom end of the Voltage Range on A-U start at 13.5V? Wouldn’t 13.5V be too high to start a train in motion?

Hence, I am wondering if Lionel intentionally disabled the A Post on this transformer included with a Scout Set! Should there be a connection from the A-Post to the Roller Arm in order that voltage can be variable on the A-Post?

Is the A-Post starting at 13.5 Volts intended for accessories? The starting point at 13.5V would seem high for that function???

There is not much information out there on this transformer.

Does anyone have any thoughts on the A-Post and how to fix?

[El_Fixes_Things]

On single throttle transformers like the 1035, the variable post is the “U” terminal. Note that the A-U range is exactly 5 volts higher than the B-U range. This is possible thanks to a 5V winding that is cut “in” for the A-U connection, and “out” for the B-U connection.
I would suspect there is something wrong somewhere, you shouldn’t be getting just 5 volts fixed. You should get 5 volts if you measure cross the A and B terminals, I believe.

-El

[OGauge_South]

Thank You… Any thoughts as to what is the likely issue? Could there be break in the winding somewhere???

At the same time, if there was a break, the B-Post would not work either??

I just wonder why there is not a connection to the throttle from the A Post. The A Post is connected only to the winding.

Attached photo shows B and U Post soldered to throttle, but the A Post is not.

Transformer is otherwise very clean

[OGauge_South]

Excuse me… it is only the B Post that is soldered to the throttle… making a complete circuit.

The A and U Posts are connected to the internal winding only. The throttle does not even reach the A Post.