Vic,
What do you mean by “I did find that couple cables from the cable box was missing but it hasn’t been touched at all.”
It could be a bad cell in the battery shorted out. I’ve had that happen suddenly on more than one occasion. Depending on the tester they use, it could read good or bad. It may depend on if the tester simulates a cranking load or not.
If the battery is completely ruled out, I wonder if a fuse for security/alarm is popped. Just a shot in the dark on that.
