The Good the Bad and the Intermittent
Part 3 – After-Market Replacement Drums
In my previous newsletter, I wrote
about keeping an eye on your camcorder’s hours meter, and monitoring the
quality of recorded video to help in determining when to consider
replacing your upper drum (which houses your video heads). We’ll
continue that discussion in this newsletter, and a little about lower
drum issues.
For several years now, we have been providing an
alternative to OEM video drums for Betacam SP camcorders. We work with
two suppliers who produce after-market upper drums and complete drums
(upper and lower). The video heads on these upper drums typically
outlast the life of original replacement heads by a great deal. One
reason for this is that the video heads are made to protrude out from
the upper drum about five to ten microns further than OEM drums. Just
like your auto’s tires, the deeper the tread – the longer they last.
Historically, BetacamSP camcorder upper drums lasted
anywhere from 600 to 1,200 hours before wearing enough to negatively
affect recordings. We began installing these after-market drums over
five years ago, and as of August 04, we have not had to replace even one
of them. In fact, nearly every one that we measure when they come in for
maintenance still have heads that have not worn down to the tip
projection of a new factory replacement head, including one camera with
over 1700 drum hours since the upper drum was installed. This
drastically cuts your video head maintenance costs. Also, the further
the heads protrude from the drum, the better the self-cleaning
properties, as the head-to-tape contact is improved.
Now, a little about lower drums. A complete drum
assembly consists of an upper drum with imbedded recording head tips
that lay down the video information at a very high rate of speed, and
the lower drum, which is stationary, and houses the motor, bearing and
shaft that the upper drum mounts to. The average drum bearings on a
Betacam camcorder last about two thousand hours. Over time the bearings
wear out and cause either audible noise that can be picked up by
microphones, unstable video, or both.
One way to diagnose this problem is to switch the
camera from save to standby mode, with a tape loaded. Only the upper
drum spins, which isolates the other sounds that are generated when you
roll tape. A growling or whining sound in standby is the sound that you
are listening for when bearings wear out. It is possible that these
sounds may come and go intermittently. One time you may here it and then
it stops. You may see horizontal instability in the picture when playing
back video in the viewfinder. Vertical objects will seem to wiggle,
caused by the shaking of the upper drum while it rotates. While TBCs
(Time Base Correctors) in playback decks correct most of this in the
beginning, eventually it will make an unusable recording.
Until now, the only fix for this worn bearing problem
has been to replace the entire complete drum assembly, because you could
not buy it separately. This complete drum is about double the cost of an
upper drum alone. For someone who has good life left on his upper drum,
having to discard the good upper drum when replacing the complete drum
is hard to swallow.
We do have an answer to this dilemma. Under special
agreement with one of our suppliers, we are able to purchase the lower
drums alone. This way we can repair the bearing problem at a fraction of
the cost of a complete drum replacement. This is good news to the
camcorder owner, especially in this time of uncertainty with the
remaining life of the Betacam format.
What about the other formats that we service? DV,
DVCAM, and DVCPRO remanufactured drum units are not yet available,
however the replacement cost of a new complete drum is substantially
less and their life expectancy is longer. Drum costs per hour of use is
very reasonable with these formats.
At Macie Video Service, we always strive to give you
the best service for your maintenance dollar. With the creation of our
Macie Uniform Standard camera alignment, Camcorder Survival kit, Warm
Card System, and our maintenance newsletters, we hope to continue to
provide these benefits to our loyal client base (Now in excess of
1,700).
Take care,
Roger