If you've been in the industry for more than ten years, you can
appreciate how far the medium has progressed. As we have advanced ourselves,
the manufacturers have advanced us with the absolute miracles of technology.
But sometimes, with those miracles, there comes a learning curve.
It has been discovered that metal tape use vs. oxide product will double the life
of tape heads. This good news also comes with some not-so-good news.
A compound that may be a product or by-product of the lubrication used to
facilitate metal tape travel "slippage" has been thought to be the cause of a
situation similar to a head clog on small format camcorders. Identified by Roger
Macie, of Dedham, MA, as "baked-on" residue, this situation has caused "clog-type"
characteristics that do not disappear with standard cleaning methods.
This advisory is not a cause for alarm as much as a call for facility maintenance
people to learn a different regimen for maintenance of the SDH series (small head
diameter) VCRs. Microscopic observation of the head followed by cautious use of a
head-cleaning cassette is recommended for dealing with this situation. Be cautious,
however. The tip penetration of the smaller diameter heads and expense of head
replacement mandates more than casual use of an abrasive head cleaning cassette. If
you don't know, leave it to a pro. Your head is a terrible thing to waste.
Roger Macie, a veteran maintenance technician, recently gave
notice to Ikegami and Sony that he was seeing a consistent pattern of a
compound amassing on the heads of SDH series machines.
Macie discovered the characteristic during a microscopic examination of the heads
that were performing consistent to a VCR with a clogged head, even after a rigorous
"Clients were coming in with badly recorded tapes with one or two heads apparently
clogged," Macie says. "Their original perception was a chroma breakup, of sorts,
that I came to see as that, and a distortion in the RF envelope."
Conventional cleaning methods such as head cleaner and/or alcohol and a clean wipe
are not effective in removing the compound.
"The only way I could effectively clean this compound off the head was to use an
abrasive cleaning tape," Macie adds. "Even then, some heads do not clean off enough
to totally eliminate the marks I saw under the microscope, and warrant a second or
third 5-second pass with the cleaning tapes: the stuff was really on there!"
One thing that may be a bit scary about this characteristic is that there is not
always an RF warning when there is a "baking" condition. There is not a large
deficiency of RF, which is the keying point of RF warning signals. There is,
however, distortion of RF envelope that will similarly distort your video.
Tom Calabro, Executive VP and Director of Engineering for
Ikegami, US, is aware of Roger's discovery, and expressed confidence that
proper maintenance was the key.
This is certainly something that has to be dealt with. "It's a minor disadvantage,
but can be dealt with by performing proper maintenance, just like changing belts.
Those cleaning tapes that you used to keep on the shelf? You'll need to use them
Dan Smith, Senior Technical Services Representative from Sony's Alabama Media
Plant, is also familiar with the challenge of the "baked-on" compound.
"The drum spins faster in the (SDH) product. And the contour of the surface of the
tape is different. These factors alone may lead to a situation that warrants a more
frequent cleaning of the heads," he says. "We are always looking to change or
modify our products to make them better, and perhaps a cleaning every 40 to 50
hours with one of our micro-abrasive cleaning cassettes is a characteristic of a
newer more superior technology.
Reinforcing Smith's opinion, a bulletin from Sony Electronics Recording Media
Productions Group says the following: "In order to remove this build up, Sony
recommends a complete cleaning every 20 hours of tape time. Sony also recommends
that a head-cleaning cassette be used every second cleaning (40-50 hours) FOR ONLY
FIVE SECONDS." Sony has also issued a service bulletin for this "build-up"
Roger has had different experiences with different build ups, and has had to run an
abrasive tape for as long as 60 seconds to remove excess mass on some heads. This
long time period is not recommended without simultaneous microscopic monitoring.
Leave it to a pro with the tools Macie states: "Checking the CTDM (compressed time
division multiplex) signal while playing back the last 15 or 20 seconds of a
recorded tape is (an accurate status indicator}. Any distortion, or breakup, in
this signal would warrant cause for concern, and perhaps some cleaning on the spot.
It is essential that the last 15 seconds be played back, and not too much less, as
you can also control track discrepancies, another symptom of the condition. These
are not always apparent with a quicker playback of 5 seconds for instance.
What's the saying? "There is no such thing as a free lunch." Here we have this
great gear that'll do it all with such nice quality, but it's not free. We are
saving money on one hand, but having to spend some of the savings on maintenance.
This "baking" characteristic, while not apparent on CDH VCRs, is as much a part of
the state-of-the-art SDH VCRs as FM audio. If you are getting the highest quality
out of the product and saving the head wear via metal recording media, you'll also
have to change your habits and perform frequent cleaning.
A thought worth some merit is to use an SDH camcorder with a separate CDH series
VCR for location production shoots when the characteristics of such work allow for
the larger package. This lessens the chance of the "keeper" being affected by the
Other principles of consideration have pointed toward tape storage. Sony
Corporations Recording Media Products Group published a comprehensive advisory in
January of 1991. MPG Technical Report Volume 6 can educate the reader on "Archival
Stability." The report is very well written and details and not-so technical
The MPG Tech report, obviously, would not be able to address newer series of tapes
like the BCT-D, BCT-Ma, and UVWT-Ma tapes which are superior to those of previous
years. Sony and other manufacturers will continue to improve their technology, and
it is certain, as long as we are in a technology that depends on heads and tapes,
we will encounter the effects inherent to the techniques.
John Matarazzo, National Technical Services Manager for Sony's Recording Media
Group agrees. "Improvements in lubricants and binding systems produce conditions
that will improve the vulnerability of tape."
Being more specific, Matarazzo says, "The new BCT-Ma series has improved
cross-linking (mechanical composition) and has systems that contribute to a
reduction in surface debris."
It's an age of new technologies that require different methods of performance and
maintenance than the technologies of the past. Field color shifts, multi-frame
distortions and repetitive dropouts do not necessarily indicate situations that
warrant extensive repair. The cause might be from manageable characteristics that
warrant attention by different methods of, and more frequent, cleanings.
Joseph Tibensky, Director of Marketing for the Recording Media Products Group,
adds, "During the normal evolution of any product, we try to make as many
improvements as possible. Sony BCT-Ma series between Betacam SP cassettes, which
have now been on the market for two full years, feature improved runnability,
cleanliness and durability beyond that of the previous BCT-M series. Since the
introduction of this formulation, and that of the similar Broadcast Master
formulation for D-2 cassettes and HMPX Hi8 formulation two years ago, the Sony
Professional Media Division has been enjoying the highest level of professional
video cassette product reliability in our history."