Many "STR-F6267" failures are actually due to a faulty startup resistor (Rstart) or a dried-out VCC capacitor on Pin 3. The latest datasheet adds a note to use Low ESR capacitors here.
Drop a comment below with your scope shots or voltage readings. The community troubleshooting thread is open.
However, I can provide a based on the typical specifications of the STR-F6200 series (STR-F6267 is a member of this family – an offline PWM controller with a built‑in power MOSFET). You can then fill in exact values from your updated datasheet.
