[jrblasde]

Good evening! I’ve done some digging around, and it looks as though there are four models which use the 66 chassis:
  1) the 1934 “early” model 66B
  2) the 1934-1935 “late” model 66B
  3) the 1935 model 66S
  4) the 1935 model 66L

    You may research (presumably) all Philco models here: https://philcoradio.com/gallery2/

    Here’s the schematic for the 66 chassis: https://philcoradio.com/library/download...l.%201.pdf