[Ron Ramirez]

Did Philco create under chassis drawings?

Yes! Not for every model (I recall some of the little Transitone home radios not having these), but most Philcos did have these.

From 1928 to early 1930, up to the model 111, Philco factory service info included a photo of the underneath of the chassis. The photos did not always reproduce well or clearly show details, so beginning with model 46, Philco switched to under-chassis drawings. These did not show all of the wiring, but do show placement and position of capacitors, resistors and other parts...which helps when you are in unfamiliar territory.