Chaos ESC Dshot600 not working?

I’ve just installed my Chaos BLHeli_S Dshot ESCs in my quad, and they’re all working fine under Betaflight 3.1.7 when configured to ONESHOT125, but one of them won’t arm or run if I change the motor configuration to any variant of DSHOT. The other three run fine using DSHOT600.

Is this something I can somehow reprogram, or does it mean the ESC is faulty? If the latter, can you send me a replacement please?

Could you let me know what flight controller you are running as that could also be the cuase of the problem… it might be a hassle but are you able to test the ESC on another FC that you know fully sports Dshot600 if yours doesnt? As there are still a few flight controllers on the market that dont fully support dshot600 yet.

Otherwise we could arrange to exchange the suspect ESC to see if that solves any issues as I am not ruling out a faulty ESC

I’m using the FrSky XMPF3E F3EVO board with built-in receiver. I can’t easily test the ESC on another FC, but what I can do is simply swap its signal connection over to one of the other three channels where the ESCs are working with Dshot600. If it still doesn’t work with Dshot600, that should indicate that the ESC is the problem, not that particular channel on the FC.

The problem lies with the FC!

The ESC that wasn’t working with Dshot600 was my #4, so I swapped its signal wire with #3 in the FC connections. When I then tested it using Betaflight Configurator, #4 ran okay with Dshot600 but #3 – now connected to #4’s channel in the FC – didn’t. So it’s channel #4 in the FC where the problem lies.

Thank you for your time.