After a flight yesterday my drone stopped working and I’m having trouble figuring out what the issue is, I thought it might be the PDB, but now I’m not sure. Details below, any help is appreciated.
The issue: I have a Matek F722-STD running on Betaflight 4.04, this board has a separate PDB with 5V running to the FC. When I plug in a LiPo, I hear the first 3 beeps from my ESCs, but I don’t hear the other two that usually follow. I can see an LED light up on my FC and also 2 on my Rx, but I get no indication that it is connecting to my Taranis, and I have zero telemetry. I am unable to arm, and there is no video transmission. … Then, when I disconnect the LiPo and plug into my computer via USB, the lights on my FC and Rx come on again (different light pattern though), no ESC beeps (which is normal) except now, I do have Telemetry and I can verify that the Taranis is connecting. … If I add the LiPo on while the USB is plugged in, I hear the 3 beeps from ESCs, but I don’t get any other functionality, and I am unable to make the motors spin up in Betaflight.
My thoughts: I initially thought that maybe the PDB was broken and it wasn’t transmitting power to the FC, but the FC and the Rx both lit up, and ESCs did initialize with 3 beeps. A multimeter shows 16.8 Volts across the ESC leads, and I was getting anywhere between 3.6 - 4.3 volts across different parts of the FC and Rx. So now I’m thinking that maybe the FC might be broken, but I can still connect to Betaflight no problem and I get telemetry when plugged into USB, so I have no idea.
Backstory on the flight: It was a gentle flight with a few tumbles from close to the ground, no broken props or any visible damage. However, after I landed at the end I noticed that the battery cables came loose and were slashed by the props at some point in the flight, however, I’m not entirely sure when it happened and it may have kept flying normally after that because it never fell from the sky, I manually disarmed at the end. Testing the battery seems to show that it’s okay, no shorts or anything, but I’m still taking safe precautions. However, it was immediately after I disconnected this pack and tried to put on another that the quad wouldn’t arm and these issues started, so I’m not sure if something might have shorted from the battery thing, or the final drop from the disarm shook something loose.
I’m not sure what’s wrong and I’m out of ideas to test and try to see what’s wrong. Does anyone have any thoughts on things I can try to test and isolate the issue? I am happy to buy and change out components if need be, but I don’t want to change out the whole FC and PDB only to find it wasn’t necessary or it didn’t fix the issue.
I really appreciate any help. Thank you