Projector SO CLOSE to being setup!

[Ryan Gallagher]

I did find these unknown status Kelmar solar cells in a junk box in the anti-booth. Perhaps useful? The arms are gonna be different, would probably be a bit of a challenge to swap the cells themselves.

Someone here with more experience might know if these can be retro-fit to a Century C. I don't know what unit they would have come off of, perhaps our prior projectors before the Century JJs?

solar cells.jpg

[Marcel Birgelen]

bts.png

To me, it looks like the mount on the left bottom. Unfortunately, the part-number on that picture seems to be broken...

[Ryan Gallagher]

To me, it looks like the mount on the left bottom. Unfortunately, the part-number on that picture seems to be broken...

That mount looks close to mine yup. Of course DX-1073 (if that is what it is saying) is not in their list. But Kelmar is still around. For Walt I would just advise reaching out to them for a Century C transducer or assembly (DX1071 or DX1074 assembly)?

The top mount pictured is more similar to Walt's, but is obviously a Simplex... there are not photos of every one, but I would assume a DX-1071 is all he needs, just the head assembly for Century.

[Josh Jones]

triangle base is RCA, the three hole c mount is a simplex. Two hole C is Century, I believe. I have a box of used Century BACP reverse scan kits I pulled from a theater that closed. PM me if your interested.

[Tim Androes]

an observation...the slit lens in your soundhead (the black tube to the left of the the sound drum) looks to be out of alignment...maybe too close so that won't help your sound any

a question...what kind of film are you planning to run? is it going to be modern film, say from about 2002 and later?

another question...what is the light source in the soundhead? is it a filament light bulb or is it an LED source?

[Walt Shires]

This is what the bracket that holds the solar cell looks like:

Screen Shot 2025-08-25 at 7.49.01 AM.png


The solar cell is glued to the clear plastic and then the wires are sort of caulked in to the black bracket in the front. When you unmount the solar cell piece - the wire are still stuck to the overall bracket.

As for the reverse system - do you need a different audio decoder to use those? Is there a benefit or is it just a different way that it's done? I only saw in the manual for the sound head (I think) that there was such a thing so don't know anything about it.

The current setup is a 9V incandescent bulb - with a DC/AC power supply. It's running at 7 volts.

I have done the setup according to the CP650 manual - (that previous photo was before the setup) and the lamp lens is close to the film, but it is focused now. I did it all - moved the bulb so the filament is in the middle, run the test films and tried my best to see the stuff on the oscilloscope (it's not as clean looking as the pictures in the manual - or is that just me and my setup?) and I've run the sound into my theater. It sounds descent - The only thing I notice is the audio is very compressed - but, maybe that is because it's trailers. It's sort of loud with little dynamic range (if that makes any sense.) I don't know if that has to do with the solar cell getting rubbed like it did. It seems like there is proper signal coming off that side of the cell (I think it's the left channel) but... I know I should try to acquire another cell now that I have that impedance drum fixed.

I have a box of trailers - a long time ago (20 years) I bought TON of them for around 50 cents each. I think I have a 100 or more. I have 2 features - the cheapest one you can get (dice rules) and one of the Star Wars ( the 90's ones).

My current idea was really just to watch trailers and such and then maybe get an interesting print or two. I don't really have much of a plan beyond that. I "rescued" the projector and some assorted stuff in the year 2000 and I had it running in my garage that time, but then I moved and that was it. Been toting all of it around for 20 years now. I've just always wanted to get it back up and running and we just recently built a theater where I could do it. The theater is a "normal" modern home theater with a laser projector, atmos speaker setup etc... the 35mm is for fun. I worked in tech for almost 20 years and am one to those that just likes older tech things now. For example, I found a 1971 jukebox - and spent a few weeks getting it up and running. It's these sorts of projects that are fun to me.

Film stuff is maybe a little bit closer to home - I did go to SF State in CA and graduated with a good old fashioned film degree! I cut my senior film on 16... so building up reels of trailers is enjoyable/nostalgic.

Ok - long way around saying that the optical setup is the setup now and I'll continue to search for a Cat 701 and then add that to the setup. But, currently I don't think any film that I have has digital data. (maybe the Star Wars does - it came with a DTS CD) So I don't think I need to be in a hurry about it (other than the 20 years it took me to get back into it _ I see everything is harder to come by now and is a lot more $)

[Ryan Gallagher]

This is what the bracket that holds the solar cell looks like:
The only thing I notice is the audio is very compressed - but, maybe that is because it's trailers. It's sort of loud with little dynamic range (if that makes any sense.) I don't know if that has to do with the solar cell getting rubbed like it did. It seems like there is proper signal coming off that side of the cell (I think it's the left channel) but... I know I should try to acquire another cell now that I have that impedance drum fixed.

I have a box of trailers - a long time ago (20 years) I bought TON of them for around 50 cents each. I think I have a 100 or more. I have 2 features - the cheapest one you can get (dice rules) and one of the Star Wars ( the 90's ones).

[Snip]

But, currently I don't think any film that I have has digital data. (maybe the Star Wars does - it came with a DTS CD)

You are still early in the tuning stage, so it could be anything, but if I knew you had a good solar cell and a tuned system and heard you say "It's sort of loud with little dynamic range", I would immediately suspect perhaps the wrong stereo format. Depending on the vintage of your trailers you may have mostly Dolby A-Type tracks (which seems likely considering you said none of them have digital tracks). Stereo A-Type sound a bit like you described if played in the incorrect Dolby SR format (5), try some again in Stereo A (4) and see if that compression/volume sensation goes away? Try mutiple trailers from different eras. That Star Wars one with DTS will definitely be SR (5).

Getting that replacement cell, head, or whole assembly will certainly help you rule out the solar cell damage.

[Josh Jones]

As for the reverse system - do you need a different audio decoder to use those? Is there a benefit or is it just a different way that it's done? I only saw in the manual for the sound head (I think) that there was such a thing so don't know anything about it.

Anything made after 2005 or so will have cyan optical soundtracks, which your incandescent reader will not reproduce well. Reverse scan has the advantage of better stereo separation and usually much better frequency response than a forward scan system. There is no change as far as the processor is concerned, as the standard preamp connections are used to interface with the reverse scan reader.

[Walt Shires]

I did find these unknown status Kelmar solar cells in a junk box in the anti-booth. Perhaps useful? The arms are gonna be different, would probably be a bit of a challenge to swap the cells themselves.

Someone here with more experience might know if these can be retro-fit to a Century C. I don't know what unit they would have come off of, perhaps our prior projectors before the Century JJs?

solar cells.jpg

Thank you for looking! Those cells look like one that I have in my junk box - which I believe is a mono cell. Either I upgraded or I was just lucky when I grabbed the stuff around the projector - I don't remember.

I do remember that I saw a message on some type of film forum that this movie theater was being remodeled to make way for a gym, and the owners offered for anyone to take the film stuff. It was the Belmont Theater in Belmont CA. My brother in law lives there remembers going to it when he was younger.

Here is a link to a short writeup about it.

https://cinematreasures.org/theaters/3395

I think it will be worth trying one of the reverse scan readers that Josh has. Then for optical tracks I should be good.