[Mondial]

Is the CT clearly marked on the replacement output transformer? It almost seems like the 450 ohm reading is across the full primary and the 240 ohms is from one plate to CT. Have you tried all the possibilities as there is no guarantee that the transformer was wired in correctly by the previous person.

According to an old data sheet for the A-3823, brown and blue are the full primary and red is the CT.

[Image: http://amradio.freeiz.com/tubestuff/thoardson.jpg]