Usually a cable box crash — especially one that  knocks out your living room TV for a whole weekend — is a minor but highly aggravating grievance. But when this happened to us at the end of last week, it actually exposed a series of screw-ups that, we learned, had us paying for hi-definition TV service that mos’ def was not hi-def for almost five months.

One of the first things we did when we moved to Chicago in July was purchase a new, high-definition-equipped, flat-screen television to replace the monstrously heavy analog set we’d had in the living room in D.C. (and decided not to ship). When we found a Samsung set we liked, the salesman at Best Buy informed us that he could give us a very good price on a floor model. We jumped at it.

Well, they wrapped the set up nicely in bubble wrap… but they apparently forgot to tell us that it was missing the wires we needed to properly connect for the Comcast hi-def service we’d signed up for.

Now, you’d have thought this would have become immediately apparent when a Comcast technician came to set up our service. But said tech, who arrived on his last job of the day on a Saturday night and made no effort to mask his displeasure, went ahead and hooked up the set with whatever equipment he had available and made no reference to any problems with the wiring.

(He also botched the set-up for our ancient console TV in the bedroom, which required a different technician to come out and correct, but that’s not directly relevant to this story.)

Except for the fact that the hi-def channels, somewhat disappointingly, didn’t look exceptionally better than the regular channels, we of untrained eye had no real reason to think there was anything amiss. Until, that is, yet another technician came to replace the cable box that went into a spontaneous coma late last week.

Turns out that the original box was hooked up with a cable that provided access to the hi-def channels, but was not actually equipped to pick up hi-def signals. Which explains why those channels didn’t look particularly hi-def. Because they weren’t.

The problem appeared to take on a measure of urgency because the box that the new tech had required the AV cable that Best Buy was supposed to have given us with the TV, but didn’t.

But I will say this much for Comcast. It’s not that they don’t screw up. Oh, not hardly. But, at least here in Chicago, our experience is that when they do screw up, they go to some lengths to correct it.

To wit, the tech identified a work-around: a box that would activate our hi-def service with a simple HDMI cable, which he indicated was easily obtainable. Not so much the box itself, but he spent several minutes making calls to other Comcast technicians until he found one — fortunately, not far from our apartment — who had one in the truck.

And yes, once he retrieved the box, completed the installation and turned on some hi-def channels, we quickly realized what we’d been missing.

LIke most of these technology fiascos, all’s well that ends well, I guess. But as soon as I can free up some time to make some inquiries, Best Buy has some explaining to do about that cable they forgot to give us, and Comcast will be made aware of the five months’ worth of hi-def service that we paid for but didn’t actually receive.