|
I downloaded the service manual. While it has more detail than I expected it also appears to cover several variants. The power supply in the manual is not the power supply that you have.
Can you verify that the mainboard in the manual is what you have? If not than the following may not apply.
J2 on the main board is the power connector. As you have 5V standby on the power supply you should have 5V on pin 2. If not there is a problem with the power supply. As there is 5V on the diodes you measured the only obvious thing I could think of would a dry joint at the connector.
Pin 1 on the J2 is the power on signal. If there is 5V on this pin the main power supply should be on. For testing you could force the power supply on by temporarily bridging pin 1 and 2 (ideally with 100-220 ohm resistor, but you usually get away with just shorting them). If the 5V, 12V and 24V rails come up the power supply is fine and the problem on the main board.
Next thing to check would be U10 on the main board. This is a regulator that should have 5V on its input and 3.3V on its output.
|