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Topic: Help with Dolby/Kelmar Reverse Scan

Joe Beres
Jedi Master Film Handler

Posts: 606
From: Minneapolis, MN, USA
Registered: Nov 2000

posted 03-08-2002 12:10 PM

I have a pair of the Kelmar reverse scan LED sound heads, and I am having a slight problem with a flutter/warble in the sound, most prevalent when I start the projector up. I think the problem is with the drum. On the problem free projector/head, the drum will spin for quite a long time with a good push. On the problem projector/head, the drum turns more easily but doesn't spin for more than a couple seconds. I put a couple drops of oil on the bearing, but that didn't seem to affect the performance. Any idea of where the root of the problem might be, and any potential remedies? Any advice would be much appreciated. THanks!

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 03-08-2002 12:23 PM

Joe
Its not unusual for these bearings grease to dry up. They are inexpensive bearings and the pair will probably not set you back more than 12 bucks. BE SURE not to get bearings that have any type of seal on them. On these bearings a shield only is permitted as a seal will load down the entire thing too much. Also get a new pair of O rings that go between the flywleel and shaft ends. They can be gotten from the same local bearing place in Madison. Been there just can't remember the name. The whole repair should not take more than a half hour not including any reader alignment that will need to be done after removing the sound drum.
MArk @ GTS

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 03-08-2002 01:04 PM

Ok...did I miss something? Did you list the type of soundhead?

Anyway...lets go for the most simple. You say the problem soundhead the drum spins MORE free yet not as long....(now this will sound stupid)...is the flywheel on on that one?

Steve

------------------
"Old projectionists never die, they just changeover!"

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Joe Beres
Jedi Master Film Handler

Posts: 606
From: Minneapolis, MN, USA
Registered: Nov 2000

posted 03-08-2002 03:40 PM

Well, it's a good day. I've actually had the time to tackle two problems that have arisen with the Ballantynes here, and both are dealt with.

Steve, it is a Kelmar/Dolby reverse scan LED head, between the topic and my post, the info was there. If there is more specific info you were looking for, I apologize, but AFIK there is only one variety of that sort of head, so I didn't track down any other info. please enlighten me if there is more for me to know.

Anyway, Steve, your post made me realize some of my own stupidity. I wasn't even thinking in terms of the flywheel. Like, Mark, I was thinking the bearings were shot. After I read your post, I had a look at the flywheel, and it was spinning on the shaft, but independently of the shaft and the drum. There was some oil that got into the works. So, I took the retaining collar, O-rings and Flywheel off. The O-rings were brittle and pretty oily, so I ditched those. I degreased everything and replaced the O-rings, put the works back together and all is well again. Thanks for your help fellas!

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Pete Naples
Phenomenal Film Handler

Posts: 1565
From: Dunfermline, Scotland
Registered: Feb 2001

posted 03-08-2002 04:23 PM

Almost very rep-set flyhweel that I've ever seen, with the BA sets that were supplied with Kalee machines being the only exception that springs to mind, have a screw of some sort through the flywheel and drum shaft. As long as this screw is in place, the situation above can't happen, BUT you can still get wow and flutter if the screw isn't tight, or there is some dimensional discrepancy between the flywheel and the shaft.

Joe, I think Steve is asking the manufacturer of the sound head, not the reverse scan kit. BTW There are several makers of reverse scan, Component Engineering and Kelmar are probably the most common though. I think you answered his question in your reply by talking about the Balantynes.

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Joe Beres
Jedi Master Film Handler

Posts: 606
From: Minneapolis, MN, USA
Registered: Nov 2000

posted 03-08-2002 04:31 PM

Pete, believe it or not, there is not a set screw in the flywheel that I could see. I was surprised. You are probably right about what Steve was asking though, I should have been more specific from the get-go. I am not positive, but I believe it is a Kelmar head, I forgot that the reverse scan was a retrofit kit.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 03-08-2002 04:41 PM

Steve G.,
Been there done that worked on em before....my ole neck of the woods so to speak. They are Ballantyne Model 7's.

Joe,
The O rings are there for some slip on start up. Follow the adjustment procedure in the manual for setting them correctly. In my experience its a good idea to replace them first though.
Mark @ GTS

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Joe Beres
Jedi Master Film Handler

Posts: 606
From: Minneapolis, MN, USA
Registered: Nov 2000

posted 03-08-2002 04:53 PM

Mark, I did replace them, and all seems to work well now. I just downloaded the manual for the head ( now that I know for certain which head it is - we weren't left one after the install apparently), but I don't see adjustment instructions. Do you have something I don't? I'd love to get a copy if you do. According to the parts diagram, I put everything together correctly though, and the drum spins just right.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 03-08-2002 07:18 PM

As to what Steve was asking...

What type of soundhead...Century, Simplex...or now in this case it is reveled Ballantyne.

Joe Kelmar does not make soundheads...merely parts that go into them. While Dolby does make soundheads (penthouse types) they don't use Kelmar parts. Therefore you initial post was incomplete and Mark had inside information.

Steve

------------------
"Old projectionists never die, they just changeover!"

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