AG-1980 is a great model of VCR. Unfortunately, as many of us learned the hard way, TGrant refurb work is somewhat shoddy, and doesn't last, needing another costly repair just a few years later. Most of us send to Deter now. But, for the moment, you have a working deck. My advise is to use it now, because I doubt it'll be in that condition longer term.
Computer is fine. Capturing is a 2000s task, and almost anything from 2010s and 2020s is fine, way beyond minimums required.
Be careful with rewinders. Most were "high speed", and tapes are too fragile. Those were almost exclusively made for the nuisance of "be kind, rewind" (aka Blockbuster video). You don't want to put important tapes in these, odds are it will mangle and "eat" them instead.
Yes, frame TBC is requird. You have the line (actually field in the 1980, aka multi-line, aka "infinite window") in that 1980. So halfway there! Line cleans the image, frame cleans the signal, you need both.
DataVideo TBC-1000 has caps concerns now. I've literally not seen a truly working DataVideo 1000 unit in at least 6 months (aside from the units I refurb'd). Several members have bought "working/tested" (BS!) units on eBay
, only to need them repaired before using (aka $500+ to the cost). But also note that some DataVideo errors can be irreparable, and you bought a paperweight.
The green AVT-8710 is sadly now another model that you cannot trust to blindly buy, especially not on eBay
. This model of TBC has gotten rare, due to failures in the past 15-20 years. The AVT-8710 was the budget model from Cypress, and most essentially lacked adequate cooling, having been housed in a tiny plastic enclosure. The latter black AVT-8710 has catastrophic flaws, and the unit actually creates dropped frames (and many others issues). Yep, it does the opposite of the intention, causing drops instead of preventing! Now then, in the past year, shady eBay sellers have started to swap these "working" black boards into failed green units. This has happened multiple times now. A few buyers found this out too late, and are now stuck with bad units. (There are some odder variants of latter greens, but those are rarer, not worth discussing here, not now.) NOTE! A member here recently bought a "green" (BLACK!) unit, and it may ended relisted soon. BEWARE!
Blackmagic is not a suggested cards, and is especially prone to issues even with line+frame TBCs in use. However, it is based on factors. Some try and try, and it fails and fails. Other try, and it squeaks by (or so is claimed). Blackmagic no longer suggest their cards for consumer analog sources, due to the common issues.
Most Youtubers are newbies themselves, and know as much (or less!) than you do. Always remember that. They're always found out in time, though some try to erase these comments, to keep pumping out their horrid advice. I see this in financials, video, computers, and others. Reddit sometimes calls out these shoddy Youtubers, but then Reddit too often has it's own groupthink issue.
Broadcast monitor is not needed whatsoever. Even I don't bother with that anymore. For starters, those drift over time, and most have drifted far outside useful values by now.
Yes, your instinct is correct here. Good VCR, made worse by poor capture card choice, and not being chased by the frame TBC. It's like buying a high end sports car, one that requires super unleaded for the turbo charged engine, special synthetic oils. Yet you fill it with regular, give it basic 10W30. The output from the car, and the output from the VCR, is ruined.
I'm having a busy week and weekend, catching up on tasks, but I sent you a PM as well.