ESCs will not startup, yet it can arm

Hardware Multirotors
1

Hi everyone, I have a miserable problem I need advice for. Prior to posting I checked every single resource, forum, and troubleshooting guide. Nothing works with my APM that used to work. The issue is that the Afro ESCs won’t do the startup chime so therefore it won’t turn the motors. Hooking up directly to the Rx or servo tester works.

Gear: APM 2.5 (3.12 currently and all firmwares failed)
-9XR with FrSky VR8-II

  • Afro ESC 20A (stock firmware)

I’ll list things I tried:

  • Arming works - all pre-arm checks good
  • Radio calibration - Throttle isn’t reversed - pwm range is 987-2100 by default. Changed to 1100-1900
  • Auto calibration failed - The APM just cycles the lights on the second powerup. Manual calibration works.
  • Flash EEPROM & reflash firmware - older versions don’t work either
  • The Afro BEC is 5.01v - I tried the other BECs too
  • I tried starting the ESCs first, then the APM
  • I tried starting the APM first with the USB, then lipo
  • I tried manually calibrating the ESC with a narrow range (1200-1800)
  • The ESC leads are correct (signal facing inward)

Ideas?

2

Have you just connected the ESCs to the receiver and calibrated them that way without the APM inline?

3

Yes, that was one of the first things I tried. I even tried using a really narrow ESC range. About 1200-1800 PWM range to see if I could raise the ESC starting point.
Nothing.