I also have a Philco 90 with push pull 45’s, and like you someone modified this set, AND also like you I’m not tech savy enough to figure out what this person did, all i know is that he bypassed the first audio transformer as the primary in it was toast, the radio plays but has very weak volume. as the only power to the speaker is coming off the plate of the last 27 tube and going to the output transformer on the speaker. There are a number of caps and resistors missing, my head is spinning from trying to figure this mess out! so my question to you Rick you show a drawing of the wiring that has all the resistor and cap values, how does this set perform the way your drawing depicts this wiring? I know this is an old thread, just wondering how you made out with it?
thanks