What to do if the quad only has the first three beeps when powering up?

When you power a quad, you'll hear 3 beeps and then 2 beeps.

The first 3 beeps are the self-checking tones for the ESC. The next 2 beeps indicate that the flight controller detects the ESC.

There are 3 reasons that can cause you can only hear the first 3 beeps.

1. The ESC/Motor protocol is not enabled. Please go to the app > Motors page to check if the ESC/Motor Protocol is set to a valid value(usually DSHOT600). If it's disabled, the flight controller can't communicate with the ESC and you can't hear the other 2 beeps and of course, you can't either arm the quad.

2. Another reason can be a bad physical connection between the flight controller and the ESC. For example, you get a faulty 8-pin cable that connects the ESC and the flight controller, or the 8-pin connector on the FC end or the ESC end is broken. To verify this, you can use 8 wires to solder directly to both ends of the ESC and the flight controller. Take the SpeedyBee F405 V3 Stack as an example, please solder the 8 wires following the pad definition below:

3. The last reason can be a faulty flight controller. You should first check if the flight controller can boot up normally. Usually, the flight controller status light(the most seen color is blue) will blink when you power the quad. If not, you may inspect the flight controller on both sides to see if there are any missing components or any visible damage. You may also try to power the flight controller through the USB port to see if it can boot up.

If only the red LED(usually indicates power is applied) is constantly on and at the same time, the flight controller doesn't heat up severely, you may try to reflash firmware in DFU mode. But if it's extremely hot(you can leave your finger on it for a long time), don't do this because it's probably burnt.

If nothing helps, please send us a video to show the status LED lights of the flight controller when powering up.