[Contributed by Chuck Schwark]

From the May, 1934 issue of the Philco Serviceman, page 4:

COLOR CODE FOR PHILCO WIRING

Philco has adopted the standard R.M.S. color code as employed by various other radio manufacturers.
This coloring of wires is held wherever possible, and there are only a very few exceptions where the
standard coloring is not used.
The chart below indicates the various colors of wires and the types of circuits in which these wires are used:
__________________________________________________

RED . . . . . . . . . Filaments and odd wires

BROWN . . . . . . . Cathodes and grounds

WHITE . . . . . . . . B+ and screens of output pentodes

WHITE w/BLACK tracer
and/or
BLACK w/WHITE tracer . . . . Plates

GREEN . . . . . . . . Grids and screen grids
__________________________________________________

This may seem like a limited selection, but remember, this is 1934 and manufacturing standards are still being formed, hashed out and adopted among the many, many radio manufacturers of the day.

Every radio manufacturer’s Engineering Department had the “not-invented-here” attitude to overcome as well when the industry was trying to standardize things.

Nowadays, after weathering and oxidizing under temp extremes and collecting dirt and dust for 70+ years, they all tend to be a muddled dark-ish blah color that obscures the original colors. Previous repairs from the 30s to 40s may have also introduced a new piece of wire here and there as well, also confusing everything.