Changing the photocell to a solar cell in a Bell & Howell Filmosound 385?

[Robert Saraceno]

Has anyone ever attempted this before on a 385?

[Maurice Leakey]

The model 385 is the earlier Bell & Howell projector housed in a wooden blimp case. It's valve (tube) amplifier is a separate unit which lives within the projector. The amplifier has a PEC (photo electric cell) which looks something like a valve.

The exciter lamp is focused through a lens assembly and projects a "slit" onto the film's soundtrack. Behind the rotating sound drum is a small mirror which directs the sound beam onto the PEC. From there on it goes through the amplifier.

With a solar cell arrangement it sits in the same position as the mirror mentioned above. The connection to the amplifier is by means of a screened cable.

The problem, as I see it, is the connection from the solar cell. You can only work on the amplifier when it is completely out of the projector. It would be necessary to fit some form of plug/socket assembly for the solar cell connection. Bearing in mind that the lead should be as short as possible it does not seem an easy thing to arrange as the solar cell will be within the projector and distanced from the amplifier.

I have a great blimp model the 8636 which has great sound and is quite similar to a 385. I can se no point in trying to change to a solar cell.

Bell & Howell Filmosound 385 16mm Sound Film Projector + accessories | #1878792133 (worthpoint.com)

[John Burgess]

Hi Robert
Usually a photo cell has around 90 volts to drive it, so there is some circuitry at the input stage you wouldn’t need.Before you do anything drastic in modifying your machine, try a solar cell on a short screened cable with a suitable plug to fit your mic socket input on the amp. You can then check it will match your amp.. Good luck , fingers crossed!
John

[Terry Sills]

I agree with John.
I did exactly that with an old Simplex 35mm projector although it didn’t have a built in amp, so I connected the solar cell to a jack plug and plugged it in to a guitar amp and it worked fine. But why change it Robert? If you are looking for a replacement PEC I can probably help.

[Robert Saraceno]

Thank you for all the responses. I'm gonna give this a shot.