Film-Tech Forum ARCHIVE: Len and solar cell assembly for Century sound head

This is topic Len and solar cell assembly for Century sound head in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Anhtu Vu (Member # 7689) on 05-20-2019, 08:33 PM:

Anyone knows where I can buy a lens / Solar cell assembly for Century sound head ?

Thanks

Posted by Gordon McLeod (Member # 33) on 05-21-2019, 10:44 AM:

Are you looking for the original excitor lamp slit lens and solar cell assemblies of replacement reverse scan readers?

Posted by Sam D. Chavez (Member # 1841) on 05-21-2019, 04:38 PM:

I saw a picture of the Century Davis loop assembly with either a Kelmar or CE reverse scan reader.

Not sure why one to need the replace the entire assembly for any reason.

Posted by Mark Gulbrandsen (Member # 72) on 05-22-2019, 09:26 PM:

THe only reason I can think of for replacing the Davis is because some of the Silicone cups and pistons were produced way out of tolerance and provided little to no damping effect. Other than that just laziness.

MArk

Posted by Randy Stankey (Member # 64) on 05-22-2019, 10:19 PM:

I've got a pretty large collection of vintage cameras and, sometimes, I have to make repairs to them.

I find that it is pretty important to keep using original parts as much as possible. When the original part is broken or damaged, use identical replacement parts. Use modern replacement parts only when original parts aren't available or if you are somehow modifying or updating a camera to modern specs.

I have a Gossen light meter that uses a mercury battery. Mercury batteries are no longer produced so, when the battery runs out in that meter, I can't use it unless I can find some workaround. Luckily, there is an adapter that allows virtual drop-in replacement of silver oxide batteries. In this case, I don't have to modify the meter in order to replace the battery.

Movie projectors are no different in my view.
I think you should try to keep original parts as much as possible.

I think that most of the parts in that assembly are perfectly fine. I think that a few parts might need repair or replacement but, with proper cleaning, repair and alignment, that reader can be put back into the machine and it will work just fine.

Posted by Sam D. Chavez (Member # 1841) on 05-23-2019, 01:24 AM:

I agree in principle with Randy as far as it goes. However, the original slit lens which was actually not part of the Century assembly, has been replaced by a RED LED reader. So, the reader should be exchanged for a known good one, maybe the one in the other soundhead if the is one.

Posted by Gordon McLeod (Member # 33) on 05-23-2019, 11:50 AM:

Usually microphonics on a century soundhead are caused by the rubber isolation gromments having become dried out and cracked

Posted by Sam D. Chavez (Member # 1841) on 05-23-2019, 08:50 PM:

The bearings in the upper and lower Davis loops are often seized as well so you get incredibly high flutter that is audible. But that is not what the issue is if I can recall, it was about buzz track showing up in the soundtrack. The original poster seems to want a shotgun solution for something that is subtle. Analog audio is pretty easy but does require some specific knowledge. I don't see an ethernet connector anywhere on the Century soundhead. Maybe I've been doing it wrong all these years.

Posted by Gordon McLeod (Member # 33) on 05-24-2019, 11:08 AM:

since it was said it was audible when ever the motor is running i tend to rule out bearsings

Posted by Will Kutler (Member # 770) on 05-29-2019, 10:22 PM:

The bearings for the upper and lower Davis arms are fairly inexpensive and standard items available at any good bearing supply.

For the isolation mounts (motor bracket pad & bushings, exciter lamp bracket), those can be fabricated from Sorbothane.

Mark G. spoke about Silicone cups and pistons. My older R5s are metal cups and pistons. Proper adjustment is when the piston travel is smooth w/no binding (centered in the cup).

Posted by Dave Macaulay (Member # 813) on 05-30-2019, 08:30 AM:

The pistons and cups are all metal, the fluid is silicone.