[exray]

Hi manny,
I always remember it on the Philco diagrams as the 'u' shaped part of the symbol as resembling the can. The can is always the negative side of the cap but that doesn't necessarily mean ground or chassis connection. In fact, none of the three caps showing in the power supply section have their negative side (can) connected to the chassis.

By all means, replace the innards of the Bakelite blocks.

Good luck,
Bill