Signal loss?

[Anmer]

Have you checked the antenna and coaxial cable?

[Truetrack]

Hi  Brian
I understand you checked the connectors mechanical and DC-continuity OK
With the deficiency comeing and and going at random
a hair-crack might be causing this.
At a time when reception is normal
one way to probe is applying Iceing Spray
(the TV-guys used it at times where boards still were repaired)
Only just one connection at a time (anyway where accessible)
e.g. In the past it was reported that the box's Ant connector had to be
resolderd.
or the other way is spot heating by hairdryer.
Watch or have someone watch for any remarkable change of blue lights.