I don't think there is a specific number anywhere. It also depends on how you finally configure your power setup.
If you use the ESC on the Outputs or the APM Power Module (JP1 removed) there is a protective fuse and diode that protect the APM which limits the Inputs and Analog rails to 500mA. (see picture for power connections layout)
This is enough if you connect your RC Receiver, Sonar, Telemetry. It would probably support the minimOSD as well (i haven't tested the current drawn by that module)
If you needed more current, you can connect a 5.0V BEC to the inputs and then you are only limited to the BEC current capabilities.
Another solution if you use the PM or ESCs power from Outputs, is to take power for servos from Outputs rail and then just route signal wires from A10/A11 for a camera gimbal. Similar for OSD, this leaves your APM protected by the fuse and the diode.
I think I may have blown my fuse.. I cant get the APM to power up using the "output" rail.. it only works if I use the servo or input rail. The fuse theory seems reasonable according to your picture. Any idea what the part number for the fuse is or how to find out?
You're right. It's the diode. All I see on it as far as markings is "JS". Any idea where I can find a replacement diode?