We have seen a number of queries about schematics, service bulletins, and service tips.  If you haven't already done so, take a look at the Philco Library (Link at the top and bottom of the Phorum page).  We have a wide variety of information available including, history, documents such as ads, sales catalogs, labels, hang tags, brochures, annotated early schematics, 1928 through 1953 Philco schematic year books, parts catalogs, parts information, service tips, and sources for parts.