I have 2 Dvl-909s all I get is a standby led when power button is pressed led goes out and nothing. I tried both power supplies I replaced the capacitors and nothing same issue as before. Anybody else have this issue? Also checked the 3.15 amp fuse and it's good. Are there any other components on the power supply board that need replaced?

I have a similar issue with a power supply from a European DVL-909. The problem with mine seems to be that the 5V Voltage is too low. A good power supply provides 5.5V and mine only 4.5V. Does not seem to be enough. Unfortunately I have not found the reason for this. Like you I was trying capacitors and also diodes but that does not seem to be the problem.

Remember these are switching power supplies so as the output voltage is fed back to the primary side any resistor or part that sends a voltage level back to the duty cycle controller or something in the controller parts effect the duty cycle generated into the coil and out to the secondary side. So if the feedback is not working properly the duty cycle is not enough to properly charge the capacitor/coil pair and that can be another reason the output voltage is low.

Of course the other reason could be something bad on one of the boards pulling it down.

Did he check all the fuses that are soldered in the power supply? They're Yellow/Gold Pico fuses (Fast acting) they will go sometimes due to any kind of short, or motor/servo stress.