I made a STUPID mistake by not reading the instructions for powering the APM carefully.
I had atttached the power module and BEC from one of the ESCs WITH THE JP1 INSTALLED.
I noticed it later when suddenly the ardupilot went off.
Now when i connect the battery it turns on normally but merely for a second.
When I connect with USB same thing
Is there any way out of this?
Without looking at a schematic to refresh my memory, it seems to me there’s a little fuse on the +5V bus that you may have blown.