dpippin, Not sure what's going on with your upgraded HDD or the unit. Someone may come up with an answer or theory in the near future... I have no good clues right now.

However, in doing a quick test of SKIP 123 to see if that'd be a simpler and quicker way to reset your machine... so you didn't have to unplug it... I ran into a POSSIBLY "NEAT" FEATURE THAT MIGHT HELP IN "CHANNEL DISCOVERY," i.e., trying to find EXACTLY what channels can be tuned.

*******************
A NEAT FEATURE FOR USE IN "CHANNEL DISCOVERY"... MAYBE?
If you've got a situation that requires a "blind-search" for channels in your area, this DVDR (my 3575 anyway) has a neat feature related to the SKIP 123 code that we use to view FW Versions.
As you know, pressing OK on the SKIP 123 menu resets the OSD Language, Clock and custom settings and deletes Timer Rec Programs. It also retains analog channels but deletes digital channels from CH+/- memory.
One additional, "new-to-me" benefit is that the CH+/- button will now go thru
ALL channels in the analog and digital tuners, 1-125 or 1-135.
To me, this gives the SKIP 123 + OK combo a new use: (1) reset the machine to factory defaults, AND (2) search ALL channels for tunability or not (blue-screen). In other words,
YOU CAN SEARCH
ALL ANALOG CHANNELS WITH CH+/- BUTTON, from 1-125. Those analog channels already in memory will still be there, and the previously blank channels will show a pic or blue screen, depending on whether they're tunable or not. No need to use the much-slower Manual Preset menu just to "discover" if any new analog channels are available.
The only
drawback on
analog is that ALL channels still "tune" with CH+/-, even blue-screens... HOWEVER, another cool thing: deleting analog channels with the Manual Preset menu is incredibly easy since the channels ratchet from one to the other AUTOMATICALLY, so all you have to do is switch to Delete > press OK and the next channel in sequence is auto-tuned. (This is true for an ADD as well.) That is, just keep pressing down-arrow > OK to Delete and let the machine switch to next channel. I deleted my 64 blank channels (62-125) in 2 minutes or less. Mine were all in sequence, but if you have blanks interspersed with good channels with "Add" checked, pressing OK is all you need to skip that channel and continue the auto-sequencing.
YOU CAN ALSO SEARCH
ALL DIGITAL CHANNELS, from 1-135. Your previously memorized digital channels will look like they're "gone," but they'll still tune with CH+/- or direct entry. The remaining, previously NOT memorized digital channels will show a pic or blue screen with CH+/-. (Except for the typical skipping of a digital channel group if XX.1 is scrambled,
as described here.) The "drawback" mentioned above for analog channels does NOT apply to digital.
Here's also where the "all-or-none" digital tuning in this DVDR HELPS you... while surfing all digital channels with CH+/-, if a channel tunes (takes a few sec), selecting Add tunes ALL subchannels in that group... don't have to separately "find" the subchannels since they'll ALL tune as a group!
This new-to-me feature provides a simple way (CH+/-) to determine which of the 1-125 or 1-135 channels are tunable in that system!
I know this works on a unit that has at least one successful auto channel scan, meaning that it found AT LEAST
ONE channel per tuner... not sure if same on a new unit with no previous channel memory. However, it might still work the same if one of the first acts in setting up a new machine (or one that channel memory is wiped out like after a HDD format) is the SKIP 123 + OK procedure???