Since the problem exists with two different playback decks - that would most
likely rule out head clogs and any playback issue that would relate back to
a single playback deck which were some of the solutions offered. Since the
image was black - as in no snow - it would most likely be because a blanking
circuit had cut in - and in fast forward / rewind basically the circuit is
defeated and what ever the heads pick up is picked up - pretty
indiscriminately - the blanking circuit usually looks for Control Track -
no control track and it gates in. It depends on the deck - I don't remember
the specifics of that particular deck - It may be that a more professional
deck may play it back enough to see an image - but it might still be
So what is it? - I believe the subject tape is an out of standard RECORDING.
The problem is not in the playback but in the original recording.
My suggestion is to first play back a known good tape - in the same standard
as the subject tape to make sure that there are no system problems. Then -
if the system is OK - my call is that the subject tape is probably recorded
out of standard. That could mean that there was a head clog on the record so
only 1 field has been recorded - or more likely that the guides were out of
alignment so that the tape is essentially its own "format"... see how easy
it is to make a new video format!!
So how do you play it back? Essentially what you need to do is to have a
service technician or someone who knows what they are doing - put the tape
in a deck and put the deck OUT of alignment to just play back that single
tape, and then put it back into alignment when it is done. I did this
frequently for forensic work and restoration work. It takes a while to do -
but is not really a hard thing to do.
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From: Association of Moving Image Archivists [mailto:[log in to unmask]] On
Behalf Of Jeff Hemmings
Sent: Tuesday, January 03, 2006 9:37 AM
To: [log in to unmask]
Subject: Re: [AMIA-L] Umatic problem-Is it a PAL tape?
The symptoms are very much like what I have seen in 8mm/hi-8
recordings many times. During the original recording process, the
VTR (or camcorder in the case of 8mm/Hi-8) does not wrap the tape
fully around the head drum leaving a non-standard, incomplete RF
envelope recorded. During search mode only portions of the RF
envelope are being scanned so a more or less complete picture is
A VTR can be forced to remain incompletely loaded around the head
drum, mimicking the recording situation; this allows the playback to
be as stable as will be possible, but still a certain portion will
display as noise since the complete signal was not recorded.
On 3-Jan-06, at 3:29 AM, Steven Spielberg Jewish Film Archive wrote:
> Thanks but -
> No picture means no picture - no snow, no dropout - nothing except
> in pause where I do get a picture.
> Yes the tape is PAL but the machine is multi - standard (PAL, SECAM
> and NTSC) - it is a Sony VO -5630 or Sony VP 7040
> Nothing happens when I play with the tracking - the audio stays the
> same, there is no meter to check.
> I don't think its Umatic/SP Hiband because the color is correct
> even in fast forward.
> I do see snow in the unrecorded area so I'm guessing misadjusted
> I am going to see about another machine this morning and hope.
> Thanks for all your help.
> Deborah Steinmetz
> Director and Client Services Librarian
> Steven Spielberg Jewish Film Archive
> Phone 972-2-5881511
> Fax 972-2-5812061
> -----Original Message-----
> From: Association of Moving Image Archivists
> [mailto:[log in to unmask]]On Behalf Of Ted Langdell
> Sent: Tuesday, January 03, 2006 12:03 AM
> To: [log in to unmask]
> Subject: Re: [AMIA-L] Umatic problem-Is it a PAL tape?
> Ted Langdell
> Ted Langdell Creative Broadcast Services
> Marysville, CA
> Main: (530) 741-1212
> What country did the tape come from?
> If it's from Europe, it may very well be a PAL standard tape, and
> need to have it converted to NTSC (our standard) in order to watch it
> on your machines.
> One easy way of finding out if it IS a PAL tape is to try playing
> it in
> a PAL deck.
> The good news is: There's obviously something on the video track of
> tape or you wouldn't see a picture of some kine using what I think is
> the "Search" function.
> What make and model of machine(s) have you tried the tape in?
> Do you have a knob labeled "tracking" and/or meter labelled
> What happens when you turn the knob slowly from the center detent
> counter-clockwise or clockwise?
> Adjust the tracking knob for maximum level (meter vane to the
> right) as
> is possible.
> After doing that, If you watch the meter while the tape is in play and
> it bounces up and down on a regular basis, it may be an indication
> the tape is the wrong standard, or was recorded with a control-track
> Many (most?) Umatic machines have a "video mute" circuit that shuts
> the video output when there's no signal present so you don't see
> on the screen with no tape in the machine, when there's no tape
> playing, or when in fast forward or rewind if the machine unthreads
> tape from around the video head drum.
> It "unmutes" in play, or if the machine has a "search" mode, which
> allows you to see the tape at speeds between still, play and say, 5x
> play in forward or reverse.
> I think you're in the "search" mode when you see some kind of video.
> If there's a problem with the tape in play, (low signal, misajusted
> tracking, wrong tape standard) it may not "unmute" and you won't see
> video. If you use the search function, it generally unmutes the video
> path in order to see some kind of picture, even if it's not something
> that would be considered playable.
> That's why you'll see snow in search at the end of a tape when you've
> gone beyond the recorded area.
> Hope this helps...
> On Jan 2, 2006, at 7:50 AM, Frank Wylie wrote:
>> OK, is the non-picture black/blank or is it "snow"? You may have
>> video head clogs; try cleaning the tape path. If the image comes
>> back briefly at regular speed after cleaning and then disappears, you
>> may have a sticky-shed tape that needs to be baked.
>> The audio head is linear and the video heads spin, so it usually
>> much longer for the audio head to pile up enough oxide, thus the
>> keeps on playing, while the video tends to clog almost instantly. In
>> the past, I have had the same problem; the reason you see it in scan
>> mode is the increased amplitude of the signal overcoming the crud in
>> the video head gap(s) but dropping below usable levels when going
>> to regular playback speed.
>> Of course, it it is PAL or SECAM like others have suggested...
>> Frank Wylie
>> Steven Spielberg Jewish Film Archive wrote:
>>> Need help! We have a Umatic tape that when played we get perfect
>>> sound but no picture on the other hand when we play it in fast
>>> forward we get fast forward picture with fast forward sound. We
>>> have tried both our machines, can someone please explain
>>> where the
>>> picture is?
>>> Thanks a lot,
>>> Deborah Steinmetz
>>> Director and Client Services Librarian
>>> Steven Spielberg Jewish Film Archive
>>> Phone 972-2-5881511
>>> Fax 972-2-5812061