Sorry this does not help but I’m on my third replacement box now due to distorted recordings and late starts.
Third box is working OK so far (after 3 weeks) the only difference is that I leave the new box in standby when not in use because of the box getting so hot if left on all the time. Don’t know whether this is relevant or not. Haven’t tried leaving the new box on all the time as yet.
Have been through all the obvious things mentioned on this site like manual tuning, checking aerial, checking cables, atenuators etc.