Along with the backwards diode, the red wire going to terminal 4 of the power transformer looks like it might be loose, as does the bus wire on the earth tab of the IEC jack.
For the STP wiring leaving power transformer terminals 6 and 7, if the shield foil sticking out touches one of the 220 ohm resistor leads going to terminal 6 or 7 on the power transformer, that can damage your power transformer.