HDHomeRun Prime with Spectrum cable

Our HOA has a basic cable package I’m paying for anyway, so I figured I might as well start to use. Problem: Circa late 2014, Time Warner (now Spectrum) started encrypting all their channels, so my analog tuning stuff would no longer work, even for what would be OTA channels if I didn’t live in a no-man’s land when it comes to any wireless signal (cell phone, TV, whathaveyou). And I don’t have room for a clunky cable set-top box. Solution: an HDHomeRun Prime box with three tuners, I could tuck away out of sight in my network stack.

Simple, right?

• Requires a cable card. Okay, no problem, went down to ye olde storefront and got a cable card (Motorola M-Card). Didn't work (bad card); exchanged it.
• Replacement card works, but wasn't validating. Called up Time Warner / Spectrum and got them to put the code into billing. Okay, validation works now.
• Go to setup channels - four of them appear (none that I'd ever watch):

• Try to watch on my Apple TV 2nd Generation devices using the HDHomeRun Prime plugin for Kodi (flashed with aTV Flash Black). I see those four channels but any attempt to watch them results in a second or two of video followed by 5-10 seconds of buffering, rinse and repeat (over gigabit Ethernet). Oh, and distorted audio and massive pixelization. 
• Try watching on my circa-2012 Panasonic DMP-BDT320 Bluray player (which is a DLNA client, the HDHomeRun Prime provides DLNA streams).

• Okay, that works. So far so good - but still only those 4 craptastic channels...
• Call up Time Warner / Spectrum and it seems I need a tuning adapter. Head on back down to the storefront. Get a box that evidently was used in 2014 and 2015 (based on the logged events still in its non-volatile memory). Hook it up. The light's supposed to stop flashing after 5-45 minutes. It's been running overnight, still flashing. Sigh.

More on this SNAFU as it progresses. At this point, I'm just in it for the challenge - and hopefully the ability to watch the Patriots lose the Superbowl.