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
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).