Videotape Surgery 101 - Part the Second |
Last updated on 29 April 2006 at 08:19:51 UTC
|by Tom "Christmas" Bozic|
My lacklustre attempt at artistic photography!
Hello again, and welcome to Part Two of Screwing Around With Things The Video Equipment Manufacturers
Don't Want You To Screw Around With
- at least, that was one of the titles for this tutorial series
that I was workshopping with my highly-paid team of writers (they're chain-bound "literary monkeys",
so I pay them with lots and lots of fruit - no calls to the RSPCA, thanks). It was promptly turned
down, due to it being a tad too long, and after some deliberation, the current title was chosen -
it was concise and pretty much explained the subject matter and target audience of the tutorials.
"101", as many of you know, is a synonym of American origin meaning "beginner" - first year
uni students over in the States (or "freshmen") would often take subjects labelled "101" in their
first semester of study (apparently, some Australian unis have adopted this convention as well).
American English has this propensity to use three-digit numbers as synonyms, such as "911"
(emergency), "411" (information), etc....with our audiovisual media being increasingly swamped
with products of US origin, these synonyms are slowly, but surely, trickling into our
vernacular, to the point that they're no longer met with blank faces over here.
But I digress (as I often do)!
Today, we're going to have some fun with the tape itself by manually spooling the reels and by
doing some repairs to broken, snapped and chewed-up tape. You'll find that, unlike the
, a lot
of the material presented here will apply to just about any type of video (and even audio) tape
- bear in mind though that, like the previous tutorial, we will be using 1.27mm (1/2") width
Video Home System (VHS)
tape as an example.
For your convienience, I have split the tutorial into the following logical sections:
I choose to continue the tutorial........NOW!0. Preparation
I assume that by working through the previous tutorial you would have established for yourself
a work area and that you are well-versed in removing tape from cassettes - if you haven't read
the previous tutorial, read it now, I'll gladly wait! You have read it? Great! Moving on...
Get yourself a cassette with tape and remove the tape - it should look something like this:
Those beautiful tape reels again!
Set aside the cassette shell - we won't be needing it, because today is all about tape, tape,
tape!1. Manual tape spooling
We're going to start off nice-and-easy and have a go at winding the tape back and
forth with our own two hands. Pretty boring, I know, but it's quite a common task when you're
messing around with tape - you might have accidentally dropped a tape reel on the floor and,
much to your chagrin, there's tape everywhere, or you've just manually removed the tape from
your VCR's tape path (next tutorial!), or the tape's a bit chewed-up/scrunched-up in the middle and
you're not keen on splicing the tape (this tutorial!), or a whole host of other scenarios you can
Pick up the storage reel with your left hand and the takeup reel with your right hand. To wind
the tape forwards, rotate the reels in a clockwise fashion and at the same time. To wind the
tape backwards, rotate the reels anti/counter-clockwise simultaneously. Simple, eh?
Now, I want you to do something a bit more challenging - when manually spooling the tape, try
to keep the distance between the reels constant! If you were to do this, you will notice the
- When there is more tape on the storage reel than the takeup reel, your right hand
moves faster than your left.
- When there is more tape on the takeup reel than the storage reel, your left hand
moves faster than your right.
- When the amount of tape is evenly distributed between the two reels, your hands move at a
As you can imagine, videotape recorders also have to factor this in when playing tapes - just
imagine what would
happen if your VCR spun both reels at a constant rate at all times, without regard to the amount of
tape on a reel at any one time? Wouldn't be an enjoyable experience, now would it!? Therefore, in
order to keep the tape running at a constant rate, the reels themselves must move at a variable
rate proportional to the amount of tape on a reel at any one time.
When you're done playing, put the tape back in the cassette and close it up.2. Tape repair
Now we move on the more fun and involved part of the tutorial! OK, how many of you here have tapes
that are currently in an unplayable condition due to the tape either being chewed up or
snapped by your hungry monster of a machine? Hmm, I see many hands shoot right up...
if you've contemplated consigning your so-called "lost cause" of a tape to the rubbish heap,
then have a little read of this section before considering such a rash decision.
First, let's assemble your Tape Repair Kit (TM). You will need:
- sharp, metal scissors (damn those plastic Kindergarten "safety-scissors" to Heck)
- clear sticky-/Sello-/Scotch-/whatever-tape (the jury's out on this one...)
- sheet of paper
- reasonably dark and soft (preferably) graphite pencil
- protractor, ruler
You might be wondering, looking at the above list, whether we're going to repair a tape or attend
a Maths lesson? I don't blame you! Bear with me, though...
Open up your cassette and remove the reels. I am assuming that one of the two situations apply
- The reels are still attached, however the tape attaching the reels is irrepairably scrunched-up
- The reels have been separated, some of the tape on either or both reels is scrunched-up
In either case, I am sorry to say this, but the chewed-up tape must go! It's not just a simple
matter of snipping off the tape and re-attaching it any-old-way - a certain degree of precision
With your ruler and pencil, draw a straight line on your sheet of paper about 5-10cm (2-4") long,
depending on the width of your tape, just like the picture below:
I used my protractor to help me draw a perfectly perpendicular (90°) line relative to
the edge of the paper, although most rulers will do just fine. You'll only really need the
protractor if you wish to make a tape cut parallel with the helically-scanned video tracks (more
on this later!)
Line the tape horizontally parallel with the edge of the sheet of paper and vertically parallel
with the line at the point you wish to make your splice
(as the pros call it), as shown.
Using your line that you drew as your guide, make a cut through the tape and the
Repeat the above steps with the other reel of tape. Now to re-unite the tape!
Take a little bit of your sticky-tape
(that's what I call it!) and stick it to the
of one snipped-off tape-end, leaving a considerable amount of overlap. Now the
painstakingly careful bit: attach the other tape-end on the underside making sure that they
line up PERFECTLY - i.e. NO vertical gap between the two tape ends, NO vertical overlap of the two
tape ends, no horizontal offset of the tape ends - these diagrams should show you what I mean.
Yes, I've hand-drawn these - quite frankly, as far as drawing on the computer is concerned,
a mouse just doesn't cut it (even optical ones like mine)! I'd so love a graphics tablet right
Trim off any excess sticky-tape from the sides of your re-united tape - we don't want our tape
to get stuck in the VCR, do we? - put the tape back in the cassette, close up the cassette and
(By the way, this would have be a good time for you to be wearing disposable surgical
gloves, for reasons explained in the previous tutorial!)
The cut tape, if you're interested...
Now put the tape in your video player and try playing and spooling it. Hopefully, the tape plays
like a charm, without too many problems. If there are problems, well....read my next tutorial
Sidebar: Videotape Anatomy 101 If you play your repaired tape, you will notice a considerably rough jump in the picture and
sound, corresponding to the splice you made. But why so rough? So far, we've been dealing with videotape without really understanding its composition or
how it works - in short, what makes "tape tick". In this sidebar, I intend to provide
a basic description of the anatomy of videotape. Although there are seemingly millions of
videotape formats out there, at the end of the day, though, videotape is videotape! Most types of videotape can be separated into three layers:
Videotape recorders make use of a variety of heads, that have the ability to read and write
sound and pictures to and from tape by either reproducing an audio and video signal based on
the current magnetic state of the tape particles or by translating an audio or video signal to
tape by changing the magnetic state of the tape particles. I will cover the particulars of the head types (along with the other components of the tape
path) in greater detail next time - for now, though, I will state that a fixed head
or (longitudinal) type reads and writes the audio track in a horizontal-linear
(longitudinal) fashion (along with the timecode track and other tracks if the tape
and recorder type support it) and a rotating head type reads and writes the video
tracks in a diagonal (or helically-scanned) fashion, much like this little
- At the bottom, there's the physical ream of tape itself - usually made out of a polyester
variant, although earlier types of videotape (made in the 50's and 60's, in particular)
have been made out of an acetate (similar to the stuff they make film out of).
- In the middle, you have a binding agent - a sort of glue that keeps the bottom and
top layers together, and of course;
- On top, you have a liberal sprinkling of metallic particles, which have the remarkable
and uncanny ability to be magnetised and to retain its magnetised state. What makes these
particles useful is the ability to exist in a number of distinct and unique magnetised
states, so that a wide variety of sounds and pictures may be stored on tape.
A track layout typical of an
analogue videotape. Obviously, this is just an exaggeration
- the actual layout of the tape particles is invisible to the naked eye
As you can see, the reason why there's such a rough jump in picture on your repaired tape
is because you have cut across
the video tracks, rather than parallel
with them. To
make the picture transition a little bit smoother, you could get out your protractor to work
out at what angle you need to make the cut - in most cases it's 45°.
A little tip: if you want to get serious about splicing tapes, you'd best be obtaining splicing
, designed especially for the purpose of attaching tape-ends together (it's a little less
stickier and messier than regular sticky-tape - and less likely to cause troubles while the tape's
wound around the tape path). Unfortunately, you'll only be able to obtain
them from specialist suppliers, so in most cases, regular sticky-tape will have to do.3. Dealing with tape reels
To finish off our tutorial today, we'll be having a look at that all-important container of
tape - the tape reel
. To ensure that your tape is running smoothly, it's important that
the reels are in good nick as well. So what
happens if your reel breaks? Most people would end up throwing the entire tape (and accessories)
away (even if there's nothing wrong with the tape!), but surely, you've read enough of this
tutorial series to realise that that is not the way we deal with things 'round here!
we're going to have a go at attaching and detaching tape from their reels.
First, spool your tape all onto one reel (either with your videotape recorder or manually) until
the only thing left on the reel is (often transparent) non-magnetic part of the tape. Now pick
up your reel and examine its core
. You will notice that the tape is attached to
the reel via a clipping bit
- to remove the clipping bit, get yourself a flat implement
(such as a butterknife - personally I used my 0.9mm flathead screwdriver from my screwdriver set),
hold your reel face-up, wedge your flat implement underneath the clipping bit, lift upwards and
you should have something like this picture:
A tapeless reel to your right (which is in perfect condition - just pulled it apart to show you)
below is the tape clipping bit.
If your reel is defective, repeat the above procedure with an expendable tape, throw away your
old reel, replace it with your new one and continue with the next paragraph (If, like me,
you were just fooling around and your reel's perfectly fine, we'll just move on...).
To put the tape back on the reel, wrap your non-magnetic part of the tape around the part where the
clipping bit used to be (making sure it's the topside
and not the underside
you!). Holding your tape taut, take your clipping bit and just clip
it back in! A bit fiddly,
but simple nonetheless."And that concludes Part Two of our tutorial - we trust that you've enjoyed your reading on ATVA.
We'll be back next time with an all new tutorial, where we take a little peek inside your VCR -
should be fun. To keep all you night-owls company, why not tune into radio 12PQ for all-night news
bulletins and some of the best music. This is Tom Bozic, on behalf of the Management here
at ATVA wishing you all a very goodnight. Goodnight!.........
......and if you're still with us, please don't forget to switch off your computer, and as an
additional fire-safety precaution, unplug it from your wall-socket. Goodnight."