@jpasan - There is now way to cure the noise, which should only be apparent on hardware Version 1 units. I replaced mine with Version 2's and so far they're fine.

@David-TP Hi, Many thanks for the response. Yes they were indeed purchased as refurbished from Amazon. I have been in touch with them and they have accepted the return. I have now placed an order for...

I have 3 Deco P9 units purchased through Amazon in June 2022. They are all working, but 2 of them have developed an annoying and continuous high pitched buzzing noise. Is there a fix for this?