LED Panel power supply issue

[zgabor]

I have a quite new LED panel which was working properly for 2,5 days. The led panel contains 130 pcs white LED in series. Now there is only ~7-8 mA flowing through the LED strip. Here is the actual power supply:

The output without load is ~495 V DC (which would cause 3.8 V drop on every every white LED). If I connect the power supply to the led strip, the voltage will be dropped and its around 340 V and the brightness is very low. I've tried to replace the capacitors on the circuit and checking resistors, diodes. I have also tested the LED's with power supply and resistor.

I don't really have idea what can cause this huge voltage drop. Any idea about this issue?
Thanks!

 

[Tony Stewart]

What voltage was on the 450V Cap? Can you list the IC specs/datasheets? Did the torroid crack? Any transient protection?

 

[zgabor]

What voltage was on the 450V Cap? Can you list the IC specs/datasheets? Did the torroid crack? Any transient protection?

Without load its around 500V!? and if the led strip is connected it's about 345V. Toroid is ok. Unfortunately, I can't identify this IC.