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 Replacement Drums Title

 

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  

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