It sounds to me like the problem could be the opposite, a ground loop where there shouldn't be one; maybe caused by the enclosure or standoffs touching something it shouldn't. Try to remove the screws holding the main board down and place a magazine or similar under it and test.
Best Regards,
Jonas
Den s?n 8 sep. 2019 kl 21:47 skrev Werner de Vos <wernerdevos@...>:
