In addition to two units of full "on Demand" programing, I have two small black digital boxes. For the past two days, they have NOT been working. Is anybody else experiencing this. Do I need to call the Comcast repairmen??
If your full set top boxes are still working, and the DTA's have quit, then first step would be call in and have them "hit" the boxes to resend the activation signals. If the hit doesn't work, then additional steps are needed.
You might be having signal issues preventing the DTA's from working. This could be from too many splitters daisy chained in the home, or wiring / connector issues either inside or outside the house.
First, check that all F connectors are snug on all connections at the DTA's and all splitters. Check that there are no poor fitting f connectors on the coax.
If your a do-it-yourselfer and had done your inside wiring, then check your connectors, remove excessive splitters and just visually check your wiring for damage.
If the wiring was done by Comcast or a previous provider, then a tech visit would be smart choice to check all the levels are proper at each outlet, and get it corrected.
If the inside wiring & splitters are very old, then it might not be up to the job of the higher frequencies that are needed by digital tv systems, and will need a going over.
It could also be due to the changing weather, and be an issue outside with the drop cable to your home.
The DTA's and full STB's don't necessarily quit working at the same moment if there is a signal issue.