No power output during transmission

[BD3OOX]

Firstly, it can be confirmed that the RF board is working properly. I tested it with another one

Where should I start detecting the problem with this green motherboard(Can control the switching of frequency bands, and the relay works normally)

[KL7MJ]

Check the setting for 3.3 TX Drive. It should be around 4. I had the same issue (I think after flashing the firmware) and it was set to 0.

[BD3OOX]

I have confirmed that TX Drive is 4

You see, the SWR shows 9.9, which is very strange

[KL7MJ]

Maybe check the solder joints on the upper board - you may have a bad connection.