Voltage on board with power module only 4V whats wrong?


i m new in this forum and i buy an apm 2.8 with his power module.

All was ok until i disconnect usb and i connect the battery.

My RC receiver is on alarm because my RC receiver have only 4.1v and it 's not enough and when i connect mission planner with the telemetry i have this horrible message Prearm check: check board voltage and i check this voltage i found 4v … so alarm of mission planner the apm bip bip bip bip bip and my rc receiver bip bip bip because voltage is under 4.2v …

how can i solve my problem . is my power module is wrong ? or my apm board ?

You heed to use standard fault finder procedures.

  1. Unplug everything from the APM except your power module, plug in the battery, measure voltage.
    If you get the same voltage then you have found the problem.
    By the way, what battery are you using?
    If the voltage looks good then proceed :

  2. Plug one thing back in, say the receiver, and measure the voltage. If it looks good keep plugging components in until you find the one that drags your voltage down.

i used 3s 3000mah battery. i have disconnected the power module just plug the battery and i have 5.02v on the power module not 5.3v is it normal ?

thanks for your answer

problem solved i remove the jumper JP1 and i remove the RED BLACK wire on RC connectors and i power the rc with RED BLACK of THE ESC connectors