I believe that the 5V regulator on my Betaflight 12A AIO board has burnt out. Now, only the receiver 5v pad gets 5V and the vtx one is dead. Is there a specific component or part to look for to fix or diagnose this problem?

Which AIO board is it? Do you have a link?

Yes, it is the BetaFPV F4 12A AIO board (older version): https://www.getfpv.com/betafpv-f4-2-4s-1...oller.html

I know Snow has some experience with 5V regulator on these FC. I will not able to check my FC until next week.

Is the VTX 5V pad only dead if you plug in a USB cable? Check the voltage on that pad it when you plug in a LiPo and if it then comes to life then it will be "by design".

I don't have one of those BetFPV FCs, but on some flight controller boards there are two 5V circuits. One that powers on when a USB cable is plugged in (for low powered devices such as the receiver), and another that only powers on when a LiPo is plugged in (for high powered devices such as a VTX). The reason for this is because it allows you to configure and test a receiver with your transmitter on the bench by just connecting a USB cable, and other devices such as the VTX don't sit there unnecessarily powered on and getting hot while you're simply just configuring the FC firmware via USB.

(28-Nov-2019, 10:09 AM)SnowLeopardFPV Wrote: Is the VTX 5V pad only dead if you plug in a USB cable? Check the voltage on that pad it when you plug in a LiPo and if it then comes to life then it will be "by design".

I don't have one of those BetFPV FCs, but on some flight controller boards there are two 5V circuits. One that powers on when a USB cable is plugged in (for low powered devices such as the receiver), and another that only powers on when a LiPo is plugged in (for high powered devices such as a VTX). The reason for this is because it allows you to configure and test a receiver with your transmitter on the bench by just connecting a USB cable, and other devices such as the VTX don't sit there unnecessarily powered on and getting hot while you're simply just configuring the FC firmware via USB.

The VTX pad is dead when the lipo is plugged in. My board receives power when plugged in via USB as well as the receiver. However, under normal operating conditions with no USB and just a lipo, the 5V regulator on the VTX pad doesn't seem to be outputting 5V.

Are you getting 5V at the other 5V pads?

(30-Nov-2019, 01:34 AM)voodoo614 Wrote: Are you getting 5V at the other 5V pads?

Yes, I am. I have tried to jerry-rig a solution by doing a double wire solder joint to the working 5V pad, but I have found that the current draw from the VTX, camera, and receiver is a bit too much for it, and causes erratic behavior in the receiver and VTX.

(30-Nov-2019, 07:15 AM)raspberrypi33 Wrote: Yes, I am. I have tried to jerry-rig a solution by doing a double wire solder joint to the working 5V pad, but I have found that the current draw from the VTX, camera, and receiver is a bit too much for it, and causes erratic behavior in the receiver and VTX.

You are probably right that it is a regulator. You have two choices, try to find the regulator through trace and DMM. Then replace it. Or buy an external step down regulator.

(30-Nov-2019, 07:35 AM)voodoo614 Wrote: You are probably right that it is a regulator. You have two choices, try to find the regulator through trace and DMM. Then replace it. Or buy an external step down regulator.

OK thanks voodoo! I was thinking about trying the second choice because it is simpler and relatively straightforward. However, my main concern is space and weight. I might just need to dig deeper and find that trace in the flight controller, like you said. Anyway, thanks for the help and support everyone!