Hello,
I know this may be a long shot but you miss 100% of the shots you don't take.
I recently purchased a Panasonic AG-1970 VCR from a seller on eBay. It said the unit was tested and worked. When I got the unit the exterior was actually in pristine condition (considering the unit is going on 30 years old). I tried playing a tape and everything seemed working just as described.
I opened it today to do a cleaning of the video heads, audio heads, rollers, gears, pathways, etc and all over the inside were what appeared to be thin black strips of something (pictures attached). When I picked up a few of the strips they just crumbled into pieces.
I reached back out to seller to see if it had ever eaten a tape or if maybe someone left a cassette in the unit for an extended period of time and when they tried to play it the tape crumbled.
They said they bought it from an estate sale and there was a tape in it and the tape the tested it was one they already had.
Again the unit works but out of caution before I put a home movie in it I wanted to check and see if someone with more experience had ever encountered something like this.
I've seen bits and pieces of old tape in a VCR but nothing as dramatic as your photos.
From the photos it looks like shredded video tape, and lots of it.
Sounds like the machine works, so you may be lucky.
First I would do a through cleaning to remove ALL of the black stuff. (not a trivial task give the number and orientation of boards in an AG-1970). Then perform other cleaning (e.g., heads, guides, etc) and refresh lube as needed. Be careful to avoid disturbing tape path alignments.
Finally run checks -several - using expendable tapes so you face no big loss if a tape is eaten by the machine.
Once you are satisfied use in good health.
Alternatively complain and send it back for full refund thus avoiding the risk associated with cleaning and servicing. Key is the detail in the description; did the seller use words like "clean." You might be able to negotiate a partial refund.
That unit had oxide shed. It's not good, and can ruin the heads irreparably.
This is why eBay "tested" and "working" is total BS, total nonsense. The sellers all lie, all incompetent idiots, when it comes to decks.
Cleaning the AG decks is not fun, not easy, not cheap.
I'd return it, or at least get a partial refund. Then again, you probably got it cheap for a reason. eBay prices are cheap, but it's because you get crap like this sent.
A person here recently told me about how he bought a "tested" and "working" VCR from eBay, and it arrived DOA, with dead roaches inside. The seller suddenly changed his tune to "well, it came from a thrift store, seemed fine to me". He fought the return, buyer had to appeal. Best of all, the seller got eBay to remove the negative feedback left by the buyer, as if it never happened. This is why eBay is not to be trusted for video gear.