8mm Forum: 16mm photocell

This is topic 16mm photocell in forum 16mm Forum at 8mm Forum.

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Posted by Jose Artiles (Member # 471) on June 25, 2006, 03:48 PM:

hi gentlemen and fellow collectors
this is my first post here.I´m a spanish film collector and i work as a film restorer/archivist in a spanish film library.I love my job and film collecting.Recently i bougth a siemens 2000 16mm projector that has the belt broken and i wonder if you can help me to find one.I need to find a tube photocell for my last "treausure", a maltese cross 16mm projector i bougth in poland.If somebody can help please let me know.Thanks for your time,gentlemen and pardon me for my poor write english.

Posted by Kevin Faulkner (Member # 6) on June 25, 2006, 05:03 PM:

Hi Jose,

Welcome to the forum and I hope you manage to find what your looking for.

There are many technical people on this forum and hopefully someone will come to rescue.

Welcome and Enjoy [Smile]

Kev.

Posted by Jose Artiles (Member # 471) on June 25, 2006, 09:51 PM:

Thanks a lot Mr. Faulkner,im sure of it.i must say that almost all collectors in spain know the famous and technical amazing "Mr. Elmo" [Wink]

.I hope all the rest of fellow members can help me to find what i looking for...specially the tube photocell for my maltese cross 16mm projector. [Big Grin]

Posted by Kevin Faulkner (Member # 6) on June 26, 2006, 07:28 AM:

Blush [Cool]

Thanks, Kev.

Posted by John Whittle (Member # 22) on July 28, 2006, 04:19 PM:

Jose,

There were about three or four difference sizes of photocell pick ups used in 16mm projectors. Antique tube suppliers do have these and you can find them on the internet. One type was 921, but I don't know if that's the type that will fit your machine.

On the other hand, it's relatively easy to convert these machines to a solar cell pick up. You no longer need the 90 volt dc bias across the tube. The solar cell should be "loaded" with a 5.6K resistor across it's leads and can feed directly into a low level input (like a microphone in) on a smp.

If you want to fix your classic, be advised that you need to check all the coupling capactors in the circuit since those are the most common failures rather than tubes. It the capactor that keeps the 90 volts across the phototube and lets the ac audio signal into the first stage of the preamp tube.

The variation in the various phototubes is both size and base pin out or wire leads.

John

Posted by Jose Artiles (Member # 471) on July 30, 2006, 01:13 PM:

Thanks a lot Mr. Whittle for your help,the 16mm maltese cross projector was made in poland in 1961,i dont have any idea about the size of the photocell of the apprience of it.Anyway,i´ll try to change the photocell for a modern cell.thanks again and have a great day!!

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