That leaves me wondering about heat, as mentioned before. Is that receiver cool enough that you could pick it up and mash it into your face without feeling like you had to throw it across the room? I think it helps in situations like this to have a memorable way of expressing the issue.

AND we still have to hear back, now.

Is the client keeping a diary of the times he's found it to be gray.

As for discovering the gray versus black, that success was a total fluke based on the idea that these guys never explain everything to us.

Next time you're there, or better yet over the phone now, be sure that symptoms are being written down very systematically.

Another odd one that became obvious to the client -- he used UHF 17 to broadcast SD video from a satellite receiver to the whole house antenna system. It quit working at night. After I lectured him on discovery through listing everything he found out, about a week later he called to say he had found that it went out at the same time every night... around dusk... had outdoor lights... turned them off one night and the problem went away. That was almost as much of a headscratcher stiil, because they were standard PAR lamps. But one of them buzzed oddly. He replaced that and the problem went away.

Write down everything and a pattern is likely to emerge.