You have replaced all the large caps, checked all the diodes and resistor and replaced the controller. The input voltage is stable. All the measured voltages across capacitors rises then slowly decrease. That would be expected if the input voltage to them stopped. Therefore, something must be breaking down and shutting down the controller. Could be a resistor, diode, small cap, transformer or EVEN a dirty PCB. I had a PCB that had a burn on it and the resistance of the carbon shut down the circuit. Grease and/or dirt might do the same thing.