APM 2.6 power issues

Hi all - hopefully someone can shed some light on some issues with my APM 2.6

It was all working OK, and then I decided to change it over to work with a PPM converter board and all went very strange.

It now only powers up correctly if I supply power via one of the centre input pins or the USB.
I am using an APM power module, and JP1 is not installed.

I don’t know what could have changed in the interim.

Thanks for any help,

Is your board a 3DR APM2.6 or clone?
What is the brand of your PPM encoder and R/C receiver?
Did you follow these Wiki instructions to correctly install the PPM encoder http://plane.ardupilot.com/wiki/common-ppm-encoder/

Hi TCIII and thanks for the reply.

Well I initially thought it was a genuine APM. It was originally purchased as a complete package from Droneshop.biz. They make no mention of it being a clone on the website, although looking at the pricing I suspect that it probably is. Not 100% sure. 3DR say its not genuine so thats what I am assuming is the case but I have asked for clarification from Droneshop.biz

The Rx is an X8R, and I am using a FrSky sBus to CPPM converter as the interface.

I didn’t follow any of the instructions that you posted the link to. I followed the instructions on Peter King of DroneShops YouTube channel.

It does all work, but only if I apply +5 to the APM via the input pins (from the BEC supplying the Rx) - this does look to me like perhaps the APM fuse or diode have gone, but I don’t know why this would be the case.