[MrFixr55]

On the Philco 60 schematic, there is that 0.015uF cap from chassis ground to the unswitched leg of the power line. One way of ensuring no "tickle" from the chassis is to install a polarized plug to ensure that the switch is on the hot side and the cap is on the neutral side.

A lot of sets have 2 caps. One each from each leg of the power inlet to chassis ground. This essentially puts the chassis at approximately 60V. I had one blow a fuse when the chassis touched the grounded frame of the display case that the chassis was on top of. (Edited 09/21/26 to make sense.) This is because one of the caps was shorted, a common problem with old paper caps across the AC Line. I suppose that on these sets grounding the chassis is important to allow for "common mode rejection" of incoming power line noise as well as completing the antenna circuit. Not grounding the chassis allows for the completion of the antenna circuit through the 2 caps to the power line, likely inducing noise.