SOLVED: Had to disconnect SBUS wire, the UART 5 and Sbus wire were interfering with one another

I have the F7 HD FC, Happymodel 2.4Ghz receiver to the Tx16s with ranger micro, and the DJI 03 air unit. 
When I disconnect the VTX from the FC then I can arm my quad fine. However when I plug in the VTX then I can no longer arm the quad. 
Any ideas on why this is happening?

The light on the receiver is a solid green showing a connection to my Radio, but when I plug it into beta flight none of the sticks show input.
 any ideas help. Thank you!

If you are using the O3 wiring harness, it includes an SBUS connection (the yellow wire on pin 6 HDL) which will interfere with your ELRS receiver if they are on the same UART. You will need to disconnect the yellow wire from the harness if you will not use the DJI remote.

Did you build this? Did it ever work as expected?

(23-Jun-2023, 08:09 PM)aerokam Wrote: Did you build this? Did it ever work as expected?

Yes it worked great, then the capacitor came unsoldered, so I resoldered it with some wire that didn't hold up well because it would get hot and smoke when i armed the quad, so I went back to the normal capacitor layout.

one of the motors also sparked and smoked in the same incident, so I thought maybe it was a short or maybe too much voltage to the components?

(23-Jun-2023, 07:50 PM)mstc Wrote: If you are using the O3 wiring harness, it includes an SBUS connection (the yellow wire on pin 6 HDL) which will interfere with your ELRS receiver if they are on the same UART. You will need to disconnect the yellow wire from the harness if you will not use the DJI remote.

I have the RX set on UART 5 and the VTX is on the UART 2. you think I should still try disconnecting the SBUS? what would be a downfall to that?

If your RX is on a completely different uart (edit: from your sbus pin) then that should not be the issue. Which FC are you using, did you check that the plug pinout matches exactly to the O3 harness as not all FC are setup to be plug-n-play. If you had a short on your FC and burned motors, then there maybe other issues with your setup.

EDIT: O3 HDL pin is connected to SBUS, so if your sbus pin is shared with UART 5, then you do need to disconnect the yellow wire or move your RX to a different UART.

(23-Jun-2023, 08:13 PM)CAAMMMM Wrote: Yes it worked great, then the capacitor came unsoldered, so I resoldered it with some wire that didn't hold up well because it would get hot and smoke when i armed the quad, so I went back to the normal capacitor layout.

one of the motors also sparked and smoked in the same incident, so I thought maybe it was a short or maybe too much voltage to the components?

Sounds to my like you might have fried something. An electrical pop on testing a motor install, during which I had to re-solder some wires that broke or got disconnected from the pads, resulted in a fried AIO. Took me awhile to find the fried component; it was on the underside of the AIO near some 5V and GND wires/pads that I had re-soldered. My soldering skills weren't very good at the time.

Based on my limited experience, I'd start trouble-shooting the board and connections between the FC and VTX. If it works when VTX is disconnected, then that seems to point toward the connection between the two. I'd zero in on those pads and connections.

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(23-Jun-2023, 09:46 PM)mstc Wrote: If your RX is on a completely different uart (edit: from your sbus pin) then that should not be the issue. Which FC are you using, did you check that the plug pinout matches exactly to the O3 harness as not all FC are setup to be plug-n-play. If you had a short on your FC and burned motors, then there maybe other issues with your setup.

EDIT: O3 HDL pin is connected to SBUS, so if your sbus pin is shared with UART 5, then you do need to disconnect the yellow wire or move your RX to a different UART.

But he said it worked before. How would it work then and not now if this were the problem?

(23-Jun-2023, 10:00 PM)aerokam Wrote: But he said it worked before. How would it work then and not now if this were the problem?

In his post he mentions the quad will arm when he unplugs the O3 and not arm only when O3 is plugged in. Typical cause for that is SBUS being on the same UART as an external RX, you cannot have two devices on the same UART, SBUS is the inverted RX pin.

(23-Jun-2023, 09:46 PM)mstc Wrote: If your RX is on a completely different uart (edit: from your sbus pin) then that should not be the issue. Which FC are you using, did you check that the plug pinout matches exactly to the O3 harness as not all FC are setup to be plug-n-play. If you had a short on your FC and burned motors, then there maybe other issues with your setup.

EDIT: O3 HDL pin is connected to SBUS, so if your sbus pin is shared with UART 5, then you do need to disconnect the yellow wire or move your RX to a different UART.

Disconnecting the Sbus worked. Thank you for your help man! its beyond appreciated

(24-Jun-2023, 02:00 AM)CAAMMMM Wrote: Disconnecting the Sbus worked. Thank you for your help man! its beyond appreciated

You said it worked fine before the issue with your capacitor. How did it work before if this was the issue?

Puzzled