[Boatanchors] Audio output transformer ID needed

[William L Howard]

I just got an audio output transformer. The only marking on it is:
13A862
X5157009

There are three wires on one side, blue, red and brown.
The other side has four wires, yellow, green,white and black

Does anyone have any information on this transformer. Which are the
input and which are the output leads?

Thanks in advance

Bill Howard