Is it the Bolt or the Fios signal?

For several weeks, Fios channel 690 has not worked on our Tivo Bolt. Sometimes it's severely pixelated, but often it's just a black screen with a V52 error message saying there's no signal. This occurs on whichever tuner is tuned to 690-- the other channels are fine and read 90-92% signal strength. But whichever tuner is on 690 reads either 67% when it's badly pixelated, or no signal at all when it's a black screen. The same problem occurs on 752, which I am told is on the same frequency....

Is it the Bolt or the Fios signal?

Is it the Bolt or the Fios signal?