Hey everyone! I am fairly new to FPV and still learning the tech side of things, but I recently purchased a GepRC Cinelog35 V2 O3 DJI PNP. After purchasing, I realized I needed the ERLS model to connect to my Radiomaster Zorro. I ended up purchasing the Radiomaster RP1 receiver to install in the drone. I installed the receiver and got it to connect to the controller when the drone was plugged into the PC but it would not connect when it was on battery power.

To start troubleshooting after hours of research, I tool my voltmeter to the drone to see if I was having a power issue (even though the receiver would have a green light on battery power, but it would not connect. This was after flashing the receiver as well).

When I took my voltmeter to the board, my probes slipped and caused a spark, I'm assuming shorting the board. After that mistake, the flashing blue light on the board is no longer there, the FC won't appear in betaflight, and the bootup sound that the drone makes has been changed; the last two beeps of the sequence now go in a descending order instead of ascending.
My guess is that I fried the FC section of this board since it is an AIO FC+ESC? I am looking for some help if there are any other suggestions other than spending another $100 on this brand new drone to replace the AIO board. Also some ideas as to why the receiver wasn't originally binding with my controller on battery power but was on USB power.
I appreciate any help that I can get! Let me know if you have any questions!

If you are able to connect to your FC in Betaflight with ONLY the USB cable, but not with the lipo, then maybe you only fried the FC's 5v regulator. In which case you could try adding an external 5v regulator which costs just a few dollars. But if you are not able to connect to your FC, there are some more trouble-shooting steps, but most likely the FC will need replacing.

As for the ELRS not working, if you had the ELRS connected to the same UART as your SBUS, then you cannot have both the O3 SBUS and ELRS connected and powered at the same time, they would not be able to communicate with the FC. You would need to disconnect the SBUS wire from your O3 or disable SERIARL RX on that port if it is on a different UART from your ELRS.

(26-Jan-2024, 11:04 PM)mstc Wrote: If you are able to connect to your FC in Betaflight with ONLY the USB cable, but not with the lipo, then maybe you only fried the FC's 5v regulator. In which case you could try adding an external 5v regulator which costs just a few dollars. But if you are not able to connect to your FC, there are some more trouble-shooting steps, but most likely the FC will need replacing.

As for the ELRS not working, if you had the ELRS connected to the same UART as your SBUS, then you cannot have both the O3 SBUS and ELRS connected and powered at the same time, they would not be able to communicate with the FC. You would need to disconnect the SBUS wire from your O3 or disable SERIARL RX on that port if it is on a different UART from your ELRS.

Thanks for the reply! I no longer have a connection to BF at all due to me shorting it out, thinking I might have to replace the brand-new FC :/

As for the ELRS not working, that could possibly be it! If I just wire to a different pad like R4 and T4 on the board and turn SERIAL RX on for port 4, do you think that would work? It's currently wired to R2 and T2.

you 100% killed the MCU

no lights on FC with either lipo or USB = buy new FC

(30-Jan-2024, 01:07 AM)ericrcrain Wrote: Thanks for the reply! I no longer have a connection to BF at all due to me shorting it out, thinking I might have to replace the brand-new FC :/

As for the ELRS not working, that could possibly be it! If I just wire to a different pad like R4 and T4 on the board and turn SERIAL RX on for port 4, do you think that would work? It's currently wired to R2 and T2.

If your FC does not light up at all, then likely it will need replacing. If you replace it with the same model, please refer to the manual.

The O3/Vista connector is using UART2 for SBUS, so if you attach a ELRS to the same UART (R2/T2), then you will need to disconnect the SBUS wire from the DJI connector. GEPRC documentation should have mentioned this, but it did not. Or you can also move ELRS to UART4, in which case you would also need to change the port settings in BF accordingly.

(30-Jan-2024, 03:25 PM)mstc Wrote: If your FC does not light up at all, then likely it will need replacing. If you replace it with the same model, please refer to the manual.

The O3/Vista connector is using UART2 for SBUS, so if you attach a ELRS to the same UART (R2/T2), then you will need to disconnect the SBUS wire from the DJI connector. GEPRC documentation should have mentioned this, but it did not. Or you can also move ELRS to UART4, in which case you would also need to change the port settings in BF accordingly.

Ahh yeah, the documentation is very confusing when it comes to where things are wired, and it says that the ERLS model comes wired to UART2. I will go ahead and buy a new FC and try wiring the receiver to UART 4 this time and will keep you all updated, I appreciate it!

(30-Jan-2024, 03:25 PM)mstc Wrote: If your FC does not light up at all, then likely it will need replacing. If you replace it with the same model, please refer to the manual.

The O3/Vista connector is using UART2 for SBUS, so if you attach a ELRS to the same UART (R2/T2), then you will need to disconnect the SBUS wire from the DJI connector. GEPRC documentation should have mentioned this, but it did not. Or you can also move ELRS to UART4, in which case you would also need to change the port settings in BF accordingly.

Okay after replacing the FC, I went to test the quad out and now my two rear motors were twitching. After checking continuity, I did not have continuity between all three wires on these two motors meaning that these motors went bad somehow (according to my research).

I then replaced them with two FOXEER DATURA 2105.5 T-MOUNT FPV MOTOR - 3650KV. These are slightly higher KV than my other two motors but according to my research, the ESC will just slow them down to match the lower KV front motors. 

After doing all of this work, I go to take off now and the drone leaves the ground but now it shakes while hovering and sounds like a swarm of bees and while testing in my room, it shot up into the ceiling. Could this be a PID tuning problem? Or maybe something else? I'm pretty lost at this point as it's been one problem after another, completely unrelated to each other.

I would like to also mention that when I installed the new AIO FC, I also flashed BlueJay to it at 48mhz.

Try swapping Bluejay to 24mhz. If you have a tune on it, then reset to default settings. You will have to retune it to work with the new but different motors.

Sorry tuning is serious dark arts level for me and I don't dabble.

(09-Feb-2024, 01:16 AM)Pathfinder075 Wrote: Try swapping Bluejay to 24mhz.  If you have a tune on it, then reset to default settings.  You will have to retune it to work with the new but different motors.

Sorry tuning is serious dark arts level for me and I don't dabble.

Okay I figured it out, just had to adjust the FC orientation but now I have another problem :/ 

My new problem is that one of my motor pads is causing a short. I desoldered the wire from the pad and the short went away, but as soon as I wire it again, it triggers my smoke stopper. Theres no visible connection between two motor pads to cause this short and I swapped the motor for another one that works so it's for sure the pad, could I have screwed something up on this board again? 

Thanks again for everyone's help, this drone is so close to being ready to fly.

(16-Feb-2024, 03:49 AM)ericrcrain Wrote: My new problem is that one of my motor pads is causing a short. I desoldered the wire from the pad and the short went away, but as soon as I wire it again, it triggers my smoke stopper. Theres no visible connection between two motor pads to cause this short and I swapped the motor for another one that works so it's for sure the pad, could I have screwed something up on this board again? 

If you're talking about the 3 pads that the 3 motor wires connect to then you will always have a short circuit being registered with the motor wires connected to those pads because there will be continuity running through the windings of the motors.

If you are trying to spin up the motors with a smoke stopper connected, it will trip because running motors draw more current that the smoke stopper allows, thus the reason it gets triggered. If everything else checks out fine, just remove the smoke stopper and carefully spin up the motors without it connected.