Video cassette - topology question
N_Cook
spool, jammed between the hank of tape and the "top" spool flange. Taking
the cover of the cassette off and removing one spool. Keeping both spools
horizontal, you unwind the scrunched loop by pulling out. Then would you
expect to have to flip one spool , one turn, to bring tape laying back to
normal? Would that removal of a twist in the tape mean the scrunched tape
has looped over the top of the spool flange before scrunching or stayed
within the plane of the normal tape passage, ie the volume of space of
width of the tape.
William Sommerwerck
Most (if not all) VCR tapes, regardless of format, are "B wind" -- the oxide
faces "out".
Most analog audio reel-to-reel formats are "A wind" -- the oxide faces "in".
Most analog audio cartridge and cassette formats are "B wind".
It doesn't matter "who struck John". You want the tape to go in straight
line from one hub to the other, with oxide facing the "outside" of the
cartridge.
Mr Cook, your writing is often unclear. You sometimes write as if English
were not your native language. You need to learn to write more clearly.
Phil Allison
"William Sommerwerck"
>
> Mr Cook, your writing is often unclear. You sometimes write as if English
> were not your native language. You need to learn to write more clearly.
>
** Not possible to write better than he thinks.
Need a brain transplant to fix that.
.... Phil
spamtrap1888
wrote:
As I understood him, he asked if videocassette tape was meant to have
a half-(or greater-) twist. Or, by extension, should it lay untwisted
like an audiotape, whether open reel or cassette.
William Sommerwerck
>> as if English were not your native language. You need to learn
>> to write more clearly.
> As I understood him, he asked if videocassette tape was meant
> to have a half- (or greater) twist. Or, by extension, should it lay
> untwisted like an audiotape, whether open reel or cassette.
Thanks.
The answer, of course, is untwisted.
Meat Plow
Could you please translate that into common English?
--
Live Fast Die Young, Leave A Pretty Corpse
Meat Plow
Oh that's what he said. Well crap, it's simply logic that tells you tapes
should not be twisted.
N_Cook
news:pan.2011.04...@emutt.macspoofer.lmao...
How do you explain a Klein bottle in text ?
It is a topological question involving twists and turns. If when a tape
runs at full tilt back and the other end hits the clear tape end stop,
failing of rate sensor. In that jarring of the tape, if it loops over the
spool and between the spool flange and the clear cover of the cassette,
before tightening up and jamming between the reel of tape and the spool
flange, will it lead to a twist in the tape .
Bob Villa
wrote:
>
> Mr Cook, your writing is often unclear. You sometimes write as if English
> were not your native language. You need to learn to write more clearly.
As with many...it is perfectly clear in his head!
Wild_Bill
audio/cart tapes).
Also, there shouldn't be any slack in the tape.. if slack exists, there are
transport problems and/or adjustments to compensate/minimize that condition.
Old VCRs had very sturdy (with real metal!) braking systems to stop reel
movement, and newer VCRs have had reel speed sensing circuits (for quite a
few years) that begin to slow the drive as the tape nears the ends.
--
Cheers,
WB
.............
"N_Cook" <div...@tcp.co.uk> wrote in message
news:ip3jik$htm$1...@dont-email.me...
William Sommerwerck
Only "continuous loop" tape cartridges use a closed loop of tape. The
infamous 8-track cartridge pulled the tape from the inside of the spool,
then fed it back to the outside. The tape has to be slightly twisted to fit
within a compact shell, but there is no net turning of the tape -- the top
edge of the tape remains on the top at all times.
I know of no tape system that used a Moebius strip.
b
> Meat Plow <mhywa...@yahoo.com> wrote in message
Yes.
Just played about with an audio reel recorder, to check the scenario
you describe.
and if the tape loops over the reel, you must then loop it back again
(the way it came, as it were) - if you continue to pull tape off the
spool there is a twist.
HTH
B.
N_Cook
news:aa16fac4-8ecc-4d72...@p16g2000vbi.googlegroups.com...
&&&&&
That was what I was trying to get an opinion on. I was aware that pulling
wire axially off the end disc of a cable drum introduced a twist in the wire
but could not decide , thinking about it for a cassette . Whether the same
applied to slipping one turn off a VCR spool by it passing over the top of
the spool in the gap between spool and transparent window on the cassette
cover, then slipping back into the volume where the tape should be, but
mangled and pulled in.
Meat Plow
Ok that makes more sense. What failure mode are you trying to explain?
Cydrome Leader
> I'm not sure I actually understand your question. However...
>
> Most (if not all) VCR tapes, regardless of format, are "B wind" -- the oxide
> faces "out".
>
> Most analog audio reel-to-reel formats are "A wind" -- the oxide faces "in".
> Most analog audio cartridge and cassette formats are "B wind".
I never knew there was a name for this oxide in or out. I recall some
horrible hong kong or taiwanese audio cassettes that were wound the wrong
way- the oxide was on the wrong side.
Scott
twists. So the spool would need to be turned at minimum, a full turn (so
that the correct side of the tape remains facing out). If you are seeing a
half twist anywhere (wrong side of the tape out), the other half of the
twist (or the return half twist) is simply folded onto the spool somewhere.
Robert Macy
examine closely, the tape may have twisted and then rolled up on one
of the reels, looks normal, and then jumped again. [happened to me]
easy to tell by shininess of tape surfaces.
I've repaired over 6 tapes that got crunched, including a pre-recorded
purchased tape.
I had to either roll enough out to find and straighten or cut off bad
section (lost 15 minutes at start of reel) and tape back to leader -
careful do not transfer human oils onto the tape
Recommend wiping the mylar substrate to smooth down the roughness,
else you run the risk of breaking a head on the VCR player, or at
least gumming it up with a lot of powder residues.
Better, if possible do NOT disassemble casette, simply make some tools
to allow you to pull the tape out of the cassette, rewind, etc. Tools
that keep the flip lid open, tools that unlock reels etc Just pull
out enough to work on the damaged section of tape, then wind back up.
Once finished, do a non-viewing wind/rewind from one end to the other
in order to get the tension and take up uniform inside the cassette.
stra...@yahoo.com
Unless it somehow managed to get over the top of the hub (EXTREMELY
unlikely), any twist in the tape will have a reverse 'mate' so that it
all cancels out. That portion will be so mangled that it might make
more sense to cut out the damage and splice it. I've been repairing
broadcast VTRs and the occasional tape and have never seen tape
slipping over the top of the hub inside of the cassette.
G²