DJI o3 air unit not powering on

[neat moat]

Hello!
I have a DJI o3 air unit on a RushFPV Blade F722 V2 digital flight stack + bl32 60a ESC
BETAFLIGHT 4.4.2, 10.9.0
Target RUSH/BLADE_F7_HD (STM32F7X2)
I can't adjust the power supply from the flight controller to the VTX in any way. At the same time, the UART ports are configured correctly:
UART2 - Serial Rx
UART3 - ESC
UART4 - VTX (MSP + Displayport)
Despite this the air unit only works over usb-c power.

• the air unit has been activated on dji assistant 2 (consumer drone series).
• the air unit has the latest firmware.
• the air unit has a green light while connected to the pc via usb-c.
  When I plug in the lipo, the stack beeps, but the air unit has no light.
  In the command line (CLI), when I enter the "get vtx" command, it displays:
  vtx_power = 0
  Allowed range: 0 - 7
  When I try to change this value, it remains unchanged.
  I've checked the connections and everything seems to be in place correctly. Is there something that needs to be done with the fc to properly power the air unit?
  Please help me solve this problem.

Additional information:

status

MCU F722 Clock=216MHz, Vref=3.26V, Core temp=50degC
Stack size: 2048, Stack address: 0x20010000
Configuration: CONFIGURED, size: 3646, max available: 16384
Devices detected: SPI:1, I2C:1
Gyros detected: gyro 1 locked dma
GYRO=ICM42688P, ACC=ICM42688P, BARO=BMP280
OSD: MSP (53 x 20)
BUILD KEY: 906e7a8dcdde44f56cf39852ee9ab377 (4.4.2)
System Uptime: 976 seconds, Current Time: 2023-10-15T18:11:05.933+00:00
CPU:32%, cycle time: 123, GYRO rate: 8130, RX rate: 15, System rate: 9
Voltage: 1 * 0.01V (0S battery - NOT PRESENT)
I2C Errors: 0
FLASH: JEDEC ID=0x00ef4018 16M
Arming disable flags: RXLOSS CLI MSP

[gusty furnace]

Are you sure that the air unit has not been connected to a 4V5 pad on the flight controller? Should theoretically still work if it is indeed powering up from the USB as the 4V5 pad should have 5V when a battery's plugged in too.

It sounds like the VTX is not wired into the FC on the right type of pad. Can you supply photos?

[rotund mesa]

Sounds more like you didnt put user1 on a switch

@neat moat

[neat moat]

Thanks for the answer. The o3 air unit is connected via a connector to the corresponding port on the flight controller (UART-4/hd-unit).

[neat moat]

Thank you very much! Please tell me how do I do this?

[rotund mesa]

well power on youre radio and quad and then connect quad to pc/laptop with betaflight open anvigate to the modes tab and there search user1 and add it to a switch

[neat moat]

I have DJI remote controller 2 and it is not connected to the air unit because there is no power supply. Sorry for the stupid questions 🙂 I'm still learning this.

[rotund mesa]

Well have you checked the user 1 thing like i said???

[neat moat]

Initially, I did not have the USER 1 mode in the modes tab. I put it there via the command "set pinio_box = 40,255,255,255". I don't understand how this will help me when the radio is not connected to fc? Thanks for the help. 🤝

[gusty furnace]

What is this USER1 thing you're referring to? I'm confused.

I wondering now what the actual problem is.

1. I thought the issue was the VTX not being powered up (at all) when plugged in with battery) but being powered up when USB is plugged in
2. But I also see in the original post that there's talk of power-levels. If power-levels are an issue, I don't think those (for the 03 Air Unit) can be controlled from Betaflight or the FC and just come down to changing settings in the goggles).
   Anyone wish to clue me up a little?

(I don't want to have the wrong end of the stick)

[rotund mesa]

Is this youre flight controller??? It uses 2 uarts?? Thats new to me you got youre 03 connected to the HD-UNIT port??

[rotund mesa]

It depends on youre flight controller for me if i dont set it to user1 my 03 wont get powered exually non vtx wont get powered except for analog.

[rotund mesa]

You need to ad it to a switch you have a lot to ad to a switch i see

[gusty furnace]

Cheers!

[rotund mesa]

Have you found it on youre fc manuel???

[gusty furnace]

I've never had to use it. I run vistas

[rotund mesa]

I also did it for my vistas to prevent them to overheat

And vistas uses 1 set of tx rx

Youre fc got 2 sets so you need youre fc manual

[gusty furnace]

I've not needed that at all for any of mine, hence me asking you about it.

[gusty furnace]

I think you might have me confused with @neat moat

[rotund mesa]

Uhm you got the same problem??

[rotund mesa]

This means that you fc is probably not correct set so youre plug doenst get powerd. You got 9 or 10volt for 03 (any vtx) maybe you need to remove a jumper or something you have seek on youre manuel witch pad you have to resolder

[gusty furnace]

No, I do not have the same problem, I have never once had to use a USER1 setting, ever.

[rotund mesa]

And you probably also have to keep in mind the switch after

[gusty furnace]

I don't know anyone else that I fly with who has had to either, to be fair.

I was just curious as to what the USER1 thing was for.

[rotund mesa]

Thats to switch on/off youre vtx

When youre on the ground

So it doesnt get burned

[gusty furnace]

Yeah, like I say, I've not come across anyone using it before, so I have learned something.

[rotund mesa]

We all do lol and some manufacturers do it for you to have it alswyas on this is for digital vtx

[neat moat]

Yes, of course. I took it to solder less. The unit is connected to its port using a cable from the manufacturer's kit.

Here is the user's manual:

[rotund mesa]

Show me youre ports tab

[neat moat]

Okay, as soon as I get to my quad

[lilac bison]

Hi @rotund mesa ! Can you please share this official information regarding to this feature for digital VTX also? I am very interested too, because two years I am flying on DJI Vista and never had to configure this on BF...
Basically, this power mode is controlled by MSP - and Arming command... Let me know if I'm wrong... ?

[rotund mesa]

Well in the mean while yeah i heard from another guy that hes is always on he never had to setup user1 . And i notice lately that mine is on after flashing BF so if u want it on a switch you can by using user1 at least my manual tells me that

[lilac bison]

Definitively, I never heard about this switch / mode setting for HD VTX neither... This can occur when some FC provide for analog VTX...
Really interested about your installation instruction if you have a link...

[rotund mesa]

Did i mis understood it???

[lilac bison]

From my understanding, this is for analogic VTX... but an issue that I am facing yet, and a friend, makes me thinking about this PINIO feature... I cannot confirm yet, and will have to try on our machines before updating about this.