Goko TC-20 problem

[Mikko]

Yesterday I transferred (or tried to) 2 films shot with 3 different cameras. Most of the footage shot with tripod. When projected they look very good but when transferred with Goko TC-20 the picture jumps up and down (about 1cm on the monitor screen) very smoothly, like waves. The image goes up 'n' down maybe 1 or 2 times per second. When swithced to 24 fps, the image waves faster.

What's the problem? What can I do for it?

Mikko

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[Kurt]

Make sure that your video camera is alligned correctly. Experiment a bit with the zoom. Some of the more modern video cameras with long zoom ranges might pose problems when using this unit. Can anyone else be more specific here?

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[salt-sg]

Please pardon my poor English.

Although I had TC-20 before, the too same condition came out.

This is the structural problem of TC-20 already reported those days.
I thought that it is because the weight of resistance of the leftside reel is fluctuated.
(It is pulled by the capstan roller, rotates too many, and a film slackens, and it is pulled again. This repetition.)

Please operate TC-20 with a very small leftside reel (50~100 feet), or apply a finger on the reel lightly and restrict rotation to it.

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[This message has been edited by salt-sg (edited November 22, 2001).]

[Mikko]

I think the problem is in the TC-20 player. I'll try tonight it with S8 camera (I can see thru view-finder if the image jumps).

M

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[Mikko]

I tested the machine with Canon S8 camera and image jumps. So it's not the camera.
Smaller reels
I had a 50 ft reel when I did the transfer.
I'll try to slow it down with finger.

Thanks!

M

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[salt-sg]

If the phenomenon comes out even case of using small reel, a cause may be in others.

I think that a sprocket, a prism, and the axis of gear which connects them have shifted a little bit

but it may be carrying out in every TC-20, the picture moves up and down. It is only a matter of degree.

I do not have solution, sorry.


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[mattias]

i've also heard the up and down jumpiness on gokos is due to the varying tension on the film, and that using your finger to increase the tension can indeed work.

also, the tc-20 works like a steenbeck flatbed, right? on a lot of the steenbecks, the prism wheel is a little "skewed", causing a similar problem where the image moves from side to side. maybe the goko has the wheel aligned the other way or something?

/matt

[MovieStuff]

I think it is simply the nature of revolving prism units that the image is slightly unsteady. I have really never seen a flatbed or any editor with a revolving prism that gave a steady image. It always seemed to "float" and kind of pulse; some worse than others, but definately nothing like the steadiness found in a simple projector.

My two cents....

Roger

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Roger Evans
MovieStuff
http://www.afterimagephoto.tv/moviestuff.html

[Mikko]

Well the "slow the reel with your finger" trick did not help.
I too think it's the prism. Can this be fixed, or are all TC-20 units like this? If they are, here's a one unit for sale! I mean, what's the point to build such a crappy machine as this?!?!
BTW, I took the film gate off, so that the film lays straight to the prism. no air between 'em. The waveing was little bit different (not so bad), but it still waves.
If someone has this machine and has troubles in adjusting the video camera (can't get the whole S8 image) try to take the film gate off. The image is in different distance and different size. With the video camera I used (Sony DSR-250P) it was easier to get the full image (no black corners etc.)
But the prism might scratch the film little bit. I don't know...

Thanks to all!

M

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[digvid]

I have a Regular8 and Super8 Goko TC-20. I agree that the pulsing is due to the nature of the rotating prism. I have heard though that if you use an older tube camera, that the pulsing is not noticable. Also, if you use a digital video camera and set the shutter speed to half the normal rate, e.g., 1/30 sec for NTSC, 1/25 sec for PAL, then the pulsing disappears also.

- digvid

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