8mm Forum: Fumeo 9119 problem, help needed

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Posted by Stig Lundberg 2 (Member # 2999) on February 18, 2017, 03:55 PM:

Need help to get my Fumeo running. Firts the axis to the fan is not moving without considerable force and the rubber belt will eventually brake. I tried to lubricate from fan side but no success. Did not figure out how to remove it without taking the whole projector apart (and I don´t have the tool for the swingweel). I might neeed a new fan with axis.
Second thing is the swingweel does not move when running the projector. I can not figure out how it is connected to the drive mechanism. Seems totally independent.

Posted by Paul Browning (Member # 2715) on February 18, 2017, 04:06 PM:

What are you describing Stig swingweel ?. Try to get some pictures up here, perhaps then we can help. If what you appear to be saying is that the motor is not turning, don't try to force this to move, as this will cause more damage to the connecting parts.

Posted by Josef Grassmann (Member # 378) on February 24, 2017, 03:10 PM:

swingwheel = flywheel

Posted by Andrew Woodcock (Member # 3260) on February 24, 2017, 03:19 PM:

Obviously the flywheel and capstan roller should be very free wheeling by hand on any machine other than one that drives this part separately and accurately by a separate motor drive belt.

I would suggest a full strip down of this part of the machine.
There shouldn't be too much involved and the bearings supporting the capstan drive shaft must have seized or at least partially seized through lack of use or lubrication, or both.

The flywheel itself is typically retained by a waved or concave spring washer and snap ring. No specialist tooling is usually required for this part of a machine.

Even if it is an external circlip, pliers are easily obtained.

On nigh on all machines, the capstan steel roller and flywheel are the driven component not the driving one.
This is why often soundtracks can be riddled with wow,especially at the outset while the flywheel gets up to full speed.

It contains a fair amount of initial inertia given its mass and takes a while to stabilize its running speed on anything other than a capstan driven mechanism, whereby the smoothing section is already at stabilized full running speed well in advance of the film getting there.

Typically, all other mechanisms rely on the thickness of the film itself to drive the capstan and flywheel properly.
This again, doesn't help as thicknesses vary and ideally you want the flywheel already turning at the matched speed of the rest of the transport system, well before the film and stripe pass over the magnetic head section or optical sound photocell

Posted by Paul Browning (Member # 2715) on February 24, 2017, 04:49 PM:

Yes its seized

Posted by Andrew Woodcock (Member # 3260) on February 24, 2017, 06:32 PM:

Good to hear you agree Paul! [Wink]

Posted by Paul Adsett (Member # 25) on February 24, 2017, 07:34 PM:

From Andrew:[/QUOTE]
It contains a fair amount of initial inertia given its mass and takes a while to stabilize its running speed on anything other than a capstan driven mechanism, whereby the smoothing section is already at stabilized full running speed well in advance of the film getting there.

Typically, all other mechanisms rely on the thickness of the film itself to drive the capstan and flywheel properly.
This again, doesn't help as thicknesses vary and ideally you want the flywheel already turning at the matched speed of the rest of the transport system, well before the film and stripe pass over the magnetic head section or optical sound photocell
[QUOTE]

On the Elmo GS1220, the flywheel is driven up to speed by a worm gear on the fan axle, even with the projector in standby mode. Unfortunately this does not eliminate start up WOW, which can be pretty awful on these machines with lubricated films. The problem is the small diameter capstan and pinch roller which does not have sufficient area and contact pressure to avoid film slippage.
On the other hand, I have had zero start up WOW problems on all my Eumig 800's and 900's, none of which idle the flywheel in stand-by mode, but do have large diameter capstans and pinch rollers, clamped together with plenty of pressure. And the flywheels on these machines are so free and well balanced that they will keep spinning for several minutes after the machine is stopped.

Posted by Phil Murat (Member # 5148) on February 25, 2017, 02:56 AM:

Hello Paul,

Concerning GS1200 Flyweel operation, let me know If what I understand is correct :

1) When machine Powered On (Not in "sound" Mode), Fan Motor initiates Flyweel spinning and maintains a "Minimum" rotation speed.

2) When "Sound Mode" is selected, Fan motor do not drive anymore Flyweel, so that Capstan shaft kept a "medium" rotation only regulated by its own inertia (like many others projectors)

Thanks in advance

Phil

Posted by Andrew Woodcock (Member # 3260) on February 25, 2017, 04:38 AM:

Yes Paul, i have observed the GS mechanism previously for the flywheel including the arm nearby, but it doesn't seem to help much and fairs only slightly better than the ST 1200 during playback, so far as wow is concerned.

Also agreed is the fact that even without these mechanisms, certainly the 900 series do very very well indeed so far as "Wow" is concerned, which proves that with perfect balance and oversized capstan rollers, things can be improved drastically in the audio department.
I have recently discovered the very same phenomena with the SH 30 also.
None of these produce design specification test figures as low as the capstan driven machines though, it has to be said.

Posted by Paul Adsett (Member # 25) on February 25, 2017, 10:42 PM:

You've got it right Phil. The GS1200 fan has a brass worm gear at the end of its shaft, which drives a little rubber roller attached to a lever arm. When the projector is in standby mode(powered up but not moving film) the little roller rests against the outer diameter of the flywheel and keeps it spinning at a speed corresponding to about 21 frames per second of film projection (i.e. mid way between 18 and 24fps). When the projector button is pushed to forward (play) a solenoid lifts the lever and the rubber roller away from the flywheel and so only the motion of the film over the capstan drives the flywheel.
Very clever, but unfortunately it does not compensate for the bad design of the small capstan and pinch roller, and start up WOW is usually significant. That's no problem at all in projecting film prints, but how these projectors were ever used for serious sound editing, where a full speed start up is required, is beyond me.

Posted by Alan Rik (Member # 73) on February 25, 2017, 10:58 PM:

When I used my GS for recordings from a dead stop I never had any wow or flutter. Right from the get go the sound recordings were great. And this was from a version one machine. The best recording one I've had. The worst one was a series II machine. No wow and flutter but uneven volume levels on both tracks. I had a GS purchased almost new in 1983 and it gave great recordings then. Sounded better than my Fisher tape deck. Pretty nice piece of kit back in the day.

Posted by Paul Adsett (Member # 25) on February 26, 2017, 11:41 AM:

Well Alan it certainly seems that the GS1200'S vary quite a bit in their performance. Of course I can only go by the performance of my own two machines, a version 1 and 2, which both exhibit start up and running WOW on some (by no means all) of my films. Something I never see on the Eumig's.
Incidentally Andrew, the WOW specification for the Eumig 938 is less than 0.4%. Not sure how that compares with the Beaulieu.

Posted by Andrew Woodcock (Member # 3260) on February 26, 2017, 11:42 AM:

Whenever I have listened to these machines Alan, it is mainly the opening scenes of the film that I can hear the pitch changes within. This concurs with what Paul says above I'd say.

Beyond that, they behave far more favourably than any ST 1200 I have ever owned, that's for sure. Only to be expected I suppose given its highly complex drive systems.

Quoted 0.2% I believe Paul btw. You certainly never hear any warbling of the track to the human ear even on very old machines. Not unless recorded this way to begin with of course like a terrible Universal 400 digest I once owned as I recall.

Family Plot it was called and the soundtrack was like nails down a chalk board! Horrible affair.

The musical string sections of lethal weapon faired only slightly better on a few ST's I once had. Painful to listen to at times.
Violins and super 8mm transport systems, quite often do not get along too well. [Big Grin]

I will dig out the sales pamphlet promoting the 708 Paul and post a photo here of it. It goes into some detail explaining how this mechanism works and benefits the filmmaker as they term it.

[ February 26, 2017, 01:01 PM: Message edited by: Andrew Woodcock ]

Posted by Paul Browning (Member # 2715) on February 26, 2017, 12:48 PM:

I think you have wow'ed and fluttered off the subject a bit here gents, FUMEO 9119 problem, not a GS, not beaulieu. Explaining how another projector works will not help one jot, if stig does not quite understand how it has failed, if you have had experience with this model and a related problem then pipe in, if not ......

Posted by Andrew Woodcock (Member # 3260) on February 26, 2017, 01:04 PM:

Yes I will post else where Paul so far as Paul A sales blurb is concerned.

We didn't hear back as often is the case here, so I figured digression as naturally often happens, was satisfactory in this case Paul.

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