Tiger Luck wrote:

Both caps have
the negative connected to the same source from the power supply and both have their
positives connected to ground. In other words, the negs of both caps are connected
together to the negative rail from the power supply and both positives are grounded,

Which is WRONG ! Read the diagram !

The negative of C311 should be grounded together with the POSITIVE of C313

Possibly a pcb legend error. I've known it happen.

Graham