Keep in mind that the U-Matic machine pulls the tape fairly far out of the
shell when it loads it, winding it around the heads inside.  This happens
more than with, say, a VCR tape.  As you know, the U-Matic mechanism has a
zillion moving parts inside, and the machine I had (before I tossed it)
would jam easily.  I used to keep the top cover off for this reason, so I
could poke around inside to make it load and unload right.  Perhaps with
this tape, the machine it was in got jammed with the tape loaded and it
remained that way for a long period of time, thus holding open the door and
exposing the tape guides (if they are near the opening), and the part of
the tape that was outside the shell wound around the heads, to whatever did
the damage.  That would be demonstrated if the remaining tape wound on the
reels inside is undamaged.   Alternatively, I suppose the tape might have
been somehow removed from a jammed machine but not wound back into the
shell, with the tape laying around outside the shell, with the door somehow
being held open.

What a horrible format this was.  As you probably know, finding players now
that work right is a challenge.  There can't be that many of them left in
the world that work well.

John Haley

On Mon, Sep 10, 2018 at 11:12 PM, Corey Bailey <[log in to unmask]>

> Hi Peter,
> Well, if it stumped you then, it stumped the wizard!
> Perhaps the client can shed some light on the situation (Storage
> conditions, storage location, etc.) Or, perhaps the content on the tape (If
> at all playable) can help.
> Please keep us posted,
> Corey
> Corey Bailey Audio Engineering
> On 9/10/2018 3:14 PM, lists wrote:
>> Today I received a ¾” u-matic tape with the strangest damage I have ever
>> seen and was wondering if anyone else had seen something similar or had an
>> idea what might have caused it.
>> We have processed nearly 500, 000 tapes and we do quite a lot of disaster
>> recovery.  I have seen tapes that have been exposed to virtually every
>> negative influence imaginable (and some not so imaginable) so I was quite
>> surprised to see something totally new.
>> The tape:
>> The tape is a 3M UCA-60 from 1984.  The cassette and hubs are white(ish)
>> plastic and the interior posts/guides and the door lock mechanism are made
>> out of black plastic.  The access door is anodized black metal.
>> The damage:
>> The tape is entirely discolored where exposed. The discoloration is only
>> near the edges a few wraps into the tape.  I have not spooled  the entire
>> tape yet to determine how far the discoloration continues.  The metal
>> cassette access door shows many small spots of corrosion on the inside of
>> door where it would be closest to the tape.  There is no corrosion on the
>> outside or the edges of the door. The tops of the metal screws on the back
>> of the cassette are badly corroded.  The entirety of the black plastic
>> tape
>> guides and black plastic door lock mechanism are very brittle/damaged, to
>> the point where they are falling apart and partially missing/destroyed.
>> There is no other indication of damage. The white plastic shell and tape
>> hubs are intact and clean and the plastic slip pads inside the cassette
>> are
>> undamaged.  There is no staining, no warping, no breakage and no
>> brittleness
>> anywhere else. Whatever happened, only the exposed tape and the black
>> plastic tape guides, the black plastic door lock, the inside of the metal
>> access door and the metal screws were affected.  Everything else looks
>> fine.
>> The damage to the tape “could” be consistent with either exposure to
>> liquid
>> or heat,  but-  there is no staining anywhere or damage to the paper label
>> to indicate liquid contamination and there is no brittleness or
>> deformation/melting anywhere else to indicate exposure to high heat.  The
>> overall damage is not really consistent with either liquid or high heat
>> damage. I even considered the unlikely possibility that the tape was
>> contaminated with some corrosive element during playback/rewind and the
>> posts were damaged as the tape was wound into the cassette.  This could
>> explain why plastic guides are nearly destroyed and the metal access door
>> was only corroded inside, near the tape, and nowhere else.  This,
>> unfortunately,  doesn’t explain the corrosion on the screws and heavy
>> damage
>> to the plastic door lock mechanism, however, since neither of these parts
>> ever touch the tape.  The plastic hub flange and slip pads inside the
>> cassette, which do contact the tape, are also undamaged.
>> Ok, how about some highly corrosive gas that reacts very aggressively with
>> one specific type of plastic (the guides and door lock mechanism) and
>> uncoated metal (the screws) but doesn’t react at all with any of the other
>> plastics in the shell/ hubs/slip pads and/or with anodized metal and
>> reacts
>> differently with the plastics in the tape (or maybe the metal in the
>> tape?)
>> in such a way as to produce a byproduct that corrodes nearby anodized
>> metal
>> (the inside of the cassette door) but dissipates quickly (so the rest of
>> the
>> anodized cassette door is unaffected).  Sound crazy?  Yes it does.  The
>> damage is so very specific and selective that I can’t figure out what
>> could
>> have happened.
>> Any ideas?  Magic?  Space aliens?
>> A very perplexed
>> Peter Brothers
>> 973-777-5055
>> [log in to unmask]
>> Audio and video restoration and re-mastering since 1983