APM 2.5 power/BEC issues

[kilby]

So my tale of woe continues

Finally got the quad up and running this today (new ESC and motor)

Had a couple of flights (after calibrating the ESCs)and things where fine until after a battery change the APM decided not to power up from the BEC (it would power up via the USB connector though)

The BEC was connected to Output 8 and obviously had the correct polarity otherwise it wouldn';t have worked with the previous 2 batteries.

On getting home I checked the BEC and it was giving 5.2V

The BEC was however able to power the APM when used via input 8, though to get the APM to talk via USB I now have to jump start it from the LiPo.

I have currently removed Jumper 1

Any suggestions on getting back to the original state of play and being able to use the output to supply power to the APM module as I hate broken things (and jump starting from the LiPo too)

Or has changing the LiPo murdered a certain Zener diode?

Thx,

Rob...

[rickp]

I don';t understand this - with JP1 removed, then the OUTPUT side is separated from the INPUT side. So your BEC on output-8 shouldn';t have been powering the APM at all.
I';m also puzzled by the fact that if you connect the BEC to the INPUT side then the USB won';t power up the APM - that suggests that something is drawing too much current from your USB port.
I think either I';m missing something (very possible, not enough coffee yet this morning), or we need more details about whats connected where...

[FragglePete]

I have my APM powered via a BEC as well with JP1 removed.  Mine is connected to Input Header No. 8.  Since using this configuration I too have to have the flight controller powered via the LiPo as the USB is not supplying enough voltage when JP1 removed, ie. with just the usb connected the leds on the board are very dim.

Pete

[kilby]

Sorry, I removed jp1 after I lost the ability to power the APM from the output end.

Any imfo I read either stated (or implied) that I should do so.

If I remove the BEC from the input side of things the usb lead can power the flight controller (and rx).