ELRS RECEIVER FREEZES WHEN MAIN BATTERY IS PLUGGED

[samsab1]

Who could help me solve this problem? It's new to me, and I'm completely stuck. I have a DAKEFPV h-74300 flight controller that's giving me a lot of trouble compared to my Speedybee controllers. My receiver is powered by the 4.5-volt pad.
When I connect the quadcopter via USB only, the receiver is active and communicates without any problems with my Radiomaster GX12 radio. But as soon as I connect the battery, the receiver freezes. The rest of the board, especially the gyroscopes, works fine, but the receiver becomes completely unresponsive to the remote control. I've checked all the connections, including the common ground of the entire assembly. I've disconnected the GPS and other accessories around the flight controller to eliminate all possible causes, but now I'm facing an incomprehensible problem: why does connecting the battery interrupt communication with the remote control?

[sensei-hacker]

why does connecting the battery interrupt communication with the remote control?

The most common answer is:

Powering up an overpowered VTX that has the antenna blasting directly into the receiver and GPS antennas completely overwhelms the signals from the handset and satellites.

But there are other possibilities.

When you say "the receiver freezes", what does that mean, exactly? Does that mean you don't see any response in the Receiver tab in Configurator?

The first thing I would check would be solder whiskers / shorts. With no power applied to the board, use a multimeter to check for continuity between any of the receiver and pads and any neighboring pads, especially vbat or vtx power.

The next thing I would check is receiver power. Using your multimeter, do the power pads for the receiver still measure 4.5 - 5.5V?

If those checks come back good, I would continue to disconnect anything else until the only things connected are the receiver and the battery. If you find that it starts working when you disconnect the rangefinder, that would be useful information.