you mean the diode on the heatsink? ...the SMPS IC doesn't even start, so
i guess right now that diode it's the least concern maybe?
Diode D104, resistor R105 and cap C108 in the schematic.
The diode shorted could stop the circuit from starting up, as well as the resistor and cap.
If the diode is open the circuit could easily destroy itself after a few seconds running, or maybe a longer run time.
If the resistor is open it could take out the diode which could then prevent startup, or destruction after a few seconds of operation.
If the cap is open the circuit could start and then destroy itself after a few seconds running (or longer).
If the cap is shorted it could stop the circuit from starting.
So the failed operating mode depends on what is bad and how it actually went bad: short or open.
When my scanner power supply blew up (smoked) i did not attempt to fix it because it had a transformer in it and various other parts which are hard to identify. Instead i just designed a new power supply which took about 30 minutes. Took about a week to get all the parts in, then after another couple hours it was up and running and ran ever since.
One thing nice about building your own power supply is that you know exactly what all the parts are and what they do, and usually you build it so it can handle more current than it actually has to so it lasts a long time.
You've got more voltages here than i had with that supply, but that's not too much of a problem as you just build several supplies rather than one single one. Some voltages can be gotten from others too, like the 3.3v can be gotten from the 5v line with a simple cheap regulator IC chip.[/quote]