These sets were made before electrolytics were used. They had large paper capacitors in one of the tar-filled cans. Unlike electrolytics which dry out, these caps have often been found to be OK even after all this time, and many just leave them connected. If after you have everything else fixed, and bring the set up easy on a variac, and you have no hum, you should be OK. Often the large wirewound resistor in these sets may have open sections. They can be replaced with individual wire wounds.
I brought up the schematic on Nostalgia Air (link attached), rotated it clockwise, and used the + button to increase the size, and find it is quite readable.
http://www.nostalgiaair.org/PagesByM...9/M0015769.pdf
BTW here's a thread over on A. R. F. that addresses the capacitor issue:
http://antiqueradios.com/forums/view...diola+++filter
Reece