8mm Forum: Chinon 7500 Sound Fault

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Topic: Chinon 7500 Sound Fault

Simon McConway
Phenomenal Film Handler

Posts: 1085
From: Doncaster, UK
Registered: Jun 2004

posted November 17, 2014 11:51 AM

Can anyone suggest how to cure the sound going muffled, then clear, then muffled and so on throughout projecting literally any film on this machine please? It's literally one second of clear sound, followed by one second of muffled sound in an on-going way throughout!

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Maurice Leakey
Film God

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

posted November 17, 2014 02:51 PM

Flywheel touching something as it rotates?

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Maurice

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted November 17, 2014 02:59 PM

Sounds like a tracking issue as the mag stripe passes the head as though you hace intermittant misalignment from a worn capstan roller or guide perhaps or worn pressure pads underneath the head maybe.

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"C'mon Baggy..Get with the beat"

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Simon McConway
Phenomenal Film Handler

Posts: 1085
From: Doncaster, UK
Registered: Jun 2004

posted November 17, 2014 03:39 PM

Thanks gents. Have checked flywheel. This is free to turn. What next?

Sound head access is very very tight!

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted November 17, 2014 03:49 PM

Does the film show any signs of lateral movement on entering or exiting the sound head section? For that matter even unusual vertical movement around the lower loop before entering the sound head section?

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"C'mon Baggy..Get with the beat"

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Simon McConway
Phenomenal Film Handler

Posts: 1085
From: Doncaster, UK
Registered: Jun 2004

posted November 17, 2014 04:06 PM

No, film enters sound head normally. Even pushing the pressure plate up by hand makes no difference.

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Rob Young.
Phenomenal Film Handler

Posts: 1633
From: Cheshire, U.K.
Registered: Dec 2003

posted November 17, 2014 04:16 PM

Simon, this could be a common sound head pressure issue.

I know this sounds odd, but what print are you running?

Andrew is correct in checking sound head pressure, but also check print width over the sound head.

Poly prints from Marketing just hated Chinons!

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Simon McConway
Phenomenal Film Handler

Posts: 1085
From: Doncaster, UK
Registered: Jun 2004

posted November 17, 2014 04:27 PM

Have got clear sound if I pull, by hand, the lower plate on the sound head, which pushes the film up, towards myself. Must be alignment then? I will try some other prints.

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Brad Kimball
Phenomenal Film Handler