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70HR/KRM info, instruction manual, tips


Philip Forrest

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One thing I noticed when I got mine working was that the spring itself needs to act like a clutch. That is, it needs to not be too tight, nor too loose. When too tight, the magazine will pull too much film after the take-up diameter increases enough to pull the lower loop. When too loose, the weight of the film will overcome the spring tension and it will bunch up in the camera. 

The problem is that the magazine rate of pull is not linear through the entire 400' and the take-up rate is dependent on the spring drive pulley in the camera. The motor itself isn't a factor here as the problem exists even if you use the manual crank to operate the magazine. So, in the last 100' the spring needs to slip and continue to pull the pulley just enough to take-up what the camera feeds through. 

Phil Forrest

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Don,

Your clip reminds me of a projector jumping film splices while viewing edited product.

(how often does film get projected these days??)

That leads me to believe that your 400' mag is outrunning the camera speed and pulling the film through the gate un-clawed (as it were), inducing slippage non-stop, rather than intermittent movement when properly clawed.

Because the camera, you indicate, works normally without the added mag, the fault may be with the mag take-up.  

That doesn't eliminate a fault in the camera, (it takes two to tango), but mag tension makes it visible.

If you have a digital high-speed-capable camera,  load your rig up with the biggest "dummy load" you can scrounge and leave the door off the side of the filmo and shoot some HS footage.  Shoot without the mag as well for "normal" and study the difference.

It will help the tech when you send it out for service.  Maybe?????

My two and a half cents worth from someone who used several filmos, including my personal one, (though none with 400' capability), many, many years ago.  We had the Arri S with big mag mostly for sports. No primes, just Ang 12-120.

I feel certain that 60 yrs. ago this problem would have been instantly recognized and solved, but, I guess most of those guys are gone now.

Hope my comments help.

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Mike, I should have added the following info about the spring belt for the 400ft mag in my previous post.

The Spring take-up Belt for 400ft mag:

Bell & Howell part number: Spring Belt Part # 10089

                                                 metal spring: 14 5/8" long & 5/32" diam. overall

                                                 looped hook at each end.

The size of the 2 looped hooks DO NOT figure into the length of the belt! (B&H edict)

Spring-Belt-for-Take-up-002.jpg

 

The 1st generation  of the 400 ft mag used a "Loading clip" to hold the light valves in the magazine open when the

small plunger was pushed in (red arrow). This makes it easy to push the film through the magazine openings.

Mag-001.jpg

Mag-set-w-clip001.jpg

A 'Shepards Hook' it was called Shepherd-s-Hook001.jpg

Worked like this (clever idea)...

Shepherd-s-Hook004.jpg

Well, those were easily lost and you never see them on eBay. One should be included with each 400 ft mag! (I only have 2 of them)

In the later years B&H came up with a smaller device to accomplish opening the valves, the 'Magazine Loading Key'

Mag-set-w-loading-key-001.jpg

This was screwed on before loading film in the dark. It opened the light valves.

The arrow points to the plunger. It is screwed on the magazine mounting screw for the camera.

IMG-9131.jpg

Mag-loading-key-003.jpg

 

After you loaded your film in the dark, and while in the dark, you would take this key off to close the valves so your film wouldn't

be exposed while mounting the mag to the camera. Then you would put this key in a very safe place so it won't get lost. lol

When the mag was mounted on the camera and the film threaded,  you put the lid or door on the camera, the door would push 

against the lever in the back by the opening in the body, and then open the valve so the film can flow freely. Red arrow.

Loading-mag-on-Camera-008.jpg

If you want to run the camera and visually see how the film is moving, you have to remember to push that lever to open the valves

so the film won't jam. A lot of juggling!!

What the magazine throat looks like:

Valve-opening-001.jpg

Figure it out?

Have you checked this system to make sure the film is flowing easily from the magazine? 

Charlie

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  • 8 months later...
On 2/7/2023 at 6:10 AM, Philip Forrest said:

Give me a day or two and I'll find my stash of belts. I can get you the part #.

Phil Forrest

I have found a source for the exact spring drive belts and have ordered 2 for my two Filmo 70HR sets. It’s a company called Magna-Tech Electronics in Florida. They have a huge catalog of cinema related items, old and new. Thank you for your help. Now I just need to build two power cables for the motors. One has a 24v motor and the other has a 110v motor. Both use 3 pin XLR style connectors for the power input.

 

my thanks to everyone who has helped with this! Especially Charlie Peich for the extra information about the shepherds hook and other internal components of the film magazine system!

Edited by Mike Owens
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On 2/10/2023 at 5:48 PM, Charlie Peich said:

Mike, I should have added the following info about the spring belt for the 400ft mag in my previous post.

The Spring take-up Belt for 400ft mag:

Bell & Howell part number: Spring Belt Part # 10089

                                                 metal spring: 14 5/8" long & 5/32" diam. overall

                                                 looped hook at each end.

The size of the 2 looped hooks DO NOT figure into the length of the belt! (B&H edict)

Spring-Belt-for-Take-up-002.jpg

 

The 1st generation  of the 400 ft mag used a "Loading clip" to hold the light valves in the magazine open when the

small plunger was pushed in (red arrow). This makes it easy to push the film through the magazine openings.

Mag-001.jpg

Mag-set-w-clip001.jpg

A 'Shepards Hook' it was called Shepherd-s-Hook001.jpg

Worked like this (clever idea)...

Shepherd-s-Hook004.jpg

Well, those were easily lost and you never see them on eBay. One should be included with each 400 ft mag! (I only have 2 of them)

In the later years B&H came up with a smaller device to accomplish opening the valves, the 'Magazine Loading Key'

Mag-set-w-loading-key-001.jpg

This was screwed on before loading film in the dark. It opened the light valves.

The arrow points to the plunger. It is screwed on the magazine mounting screw for the camera.

IMG-9131.jpg

Mag-loading-key-003.jpg

 

After you loaded your film in the dark, and while in the dark, you would take this key off to close the valves so your film wouldn't

be exposed while mounting the mag to the camera. Then you would put this key in a very safe place so it won't get lost. lol

When the mag was mounted on the camera and the film threaded,  you put the lid or door on the camera, the door would push 

against the lever in the back by the opening in the body, and then open the valve so the film can flow freely. Red arrow.

Loading-mag-on-Camera-008.jpg

If you want to run the camera and visually see how the film is moving, you have to remember to push that lever to open the valves

so the film won't jam. A lot of juggling!!

What the magazine throat looks like:

Valve-opening-001.jpg

Figure it out?

Have you checked this system to make sure the film is flowing easily from the magazine? 

Charlie

 

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