I have two FMCOMMS3 boards and one custom board using an AD9361 chip. The devices were working as the should until the two FMCOMMS3 boards started to have intermittent outputs. The outputs resembled a random modulation. They were initially used on the a zynq board with the Linux OS, but once this occurred, I performed tests on a separate board with a no-OS setup and saw the same thing. When I tried to transmit a basic tone with the no-OS setup, I saw about different outputs. One was the perfect tone and other others looked like random modulations. Once powered on the output wouldn't change and I saw no tuning failures.
I eventually ran into the same issue on the custom board that used the FMCOMMS3 board as a reference design. What could have caused this? Are there any known issues? The only thing linking these three boards together is the AD9361 and the same issue exists across all three.