Is the main rectifier diode a black ractangular box with 4 legs, one
labled +, one labled -, and two labeled with s-shaped swigly lines?
Yes, you've found it Those squiggly lines are little sine waves, the
conventioanl AC symbol. See my other message for how to test it.
Should I get continuity between the s-shaped swigglely
NO!. Those should be open-circuit both ways!