Cable box not working

I've had an ongoing issue with my cable box - for nearly a month (in March) it wouldn't work without performing some form of reset, either unplugging it and then plugging it back in or having xfinity send a signal to it.  Then it seemed to work fine for most of April, but now it's gone back to not working without a reset.  Yesterday it wouldn't come on at all until around 6 in the evening, and today it is again not coming on at all.  I've checked every connection, and trying different connecting cables hasn't helped either.  This has been very frustrating.  We have a rather old (I'm guessing at least 25 years old) Motorola box that is property of Xfinity, and it probably needs to be replaced, regardless of whether or not that is the main problem.

We have internet and phone with Xfinity, and both of those have had no issues - it's just the cable.

Please help.