8mm Forum: Bell & Howell optical system

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Topic: Bell & Howell optical system

Robert Crewdson
Phenomenal Film Handler

Posts: 1031
From: UK
Registered: Jun 2013

posted August 04, 2013 04:44 AM

The manual for a Bell & Howell in a wooden blimp case says, in regard to cleaning the optical system, 'The mirror, which can be seen by looking down behind the sound drum from in front of and above the machine, should be cleaned regularly'.
Although I have cleaned the sound drum, and lens facing the exciter lamp, I have never seen any mirror. Could someone with one of these older machines post a picture of what I am supposed to be looking for.
Thanks.

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Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted August 04, 2013 09:45 AM

Robert
The mirror is so small I would suggest it's left all to itself. It's behind the sound drum and reflects the sound track at 90 degrees to the photo cell.

Perhaps a good puff of air would be O.K., but it's my advice to not even go looking for it.

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Maurice

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Robert Crewdson
Phenomenal Film Handler

Posts: 1031
From: UK
Registered: Jun 2013

posted August 04, 2013 09:58 AM

I'll leave it alone Maurice, the reason I asked is because although I cleaned the drum and lens facing the exciter lamp, the sound improved, but was still not possible to distinguish all words. I thought of this after reading the posts about vacuum tubes being superior in sound. The older B&H projectors only have a tone control, whereas the more modern have bass and treble controls.

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Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted August 04, 2013 10:52 AM

Old blimp model Bell & Howells are now getting on in age, and if they haven't been stored properly the reflective coating on the mirror develops cracks and the coating wears off.

This is serious trouble as the only answer is a new mirror. Gordon Ogbourne may have a spare, but it's going to need professional attention for the replacement.

You could try laying the projector on its side and partially removing the amplifier to see if the photocell is clean and seated in its base firmly. Be wary of the flying lead.

--------------------
Maurice

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Robert Crewdson
Phenomenal Film Handler

Posts: 1031
From: UK
Registered: Jun 2013

posted August 04, 2013 11:20 AM

Thanks.

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