Film-Tech Forum ARCHIVE: kinoton FP38 35mm/16mm shutter ghosting

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Posted by Kirk Futrell (Member # 5006) on 09-28-2012, 04:37 PM:

I'm having an issue with the shutter speed ramping up every few seconds when the projector is set to variable speed. This causes shutter ghosting. It doesn't seem to happen when we play at 24fps 35mm non variable. We have two of these and both seem to do it, I probably overlooked something in the pidgin german manual. (Which is a hilarious read, btw.) Any ideas?

Posted by Kirk Futrell (Member # 5006) on 12-11-2012, 05:43 PM:

Hate to bring this one back up but I have a 18fps 35mm screening of Dr. Caligari this friday and would love some advice on what is happening. There seems to be an issue of the intermittent and shutter getting out of sync every 4 or 5 seconds which causes downward ghosting to occur then clear up then occur, etc. THis effect seems to be worst from 16fps to 18fps. It does not happen at 24 fps.

I know there are some Kinoton experts on here. Any one I should call if you don't have time?

Thanks in advance.

Posted by Steve Guttag (Member # 268) on 12-11-2012, 11:50 PM:

What vintage Kinoton is it (year)...is it a Premiere or before 2007?

Once you have that information...then measure the shutter blade...what is the degree of opening (or the degree of the blade...I can work from either way). Variable speed projectors are supposed to be fitted with a less light efficient blade to deal with this. The problem arises since the Kinoton E will change shutter speed such that as one crosses from 21-19fps, it will switch to "3-wing" mode.

Since most cinemas will project only 24fps or 25fps, they can gain an additional level of light efficiency by optimizing the shutter blade for those two speeds. It sounds like your machines were fitted with the 24/25fps blades. This would be even more likely if your machines had the variable speed retrofitted.

Posted by Kirk Futrell (Member # 5006) on 12-12-2012, 06:34 PM:

Steve thanks for your help!

Its from 2001, i think, its serial number is B0789 if that helps. I don't believe it has been retrofitted, as the equipment has not changed since it was installed in 2001.

If I am measuring correctly the shutter is 90 degrees, (so is the opening, but I guess that is obvious). It has two blades. Also I got a reply from someone at kinoton and the folks at the factory wanted to know the version of software of the intermittent IC chip. Its Blen3 FPI v. 1

Posted by Steve Guttag (Member # 268) on 12-12-2012, 09:44 PM:

The circa 2001 machines had a bad batch of Blendreg chips and you could get ghosting but it was more random and one didn't have to be doing variable speed. I don't think that is your problem though.

Also in those machines they were more apt to vary the pull-down (I'm betting your loops are more erratic and it jumps up/down quite a bit (though it shouldn't show on screen). Your shutter blade is likely black too (rather than the current silver ones).

The Vario shutter for a pre-2007 machine was a 110-degree blade. Note too, the silver ones are thinner/lighter so the shutter motor does not have to fight as much mass when moving it. If you change it, you will likely need new hubs too in order to get them to properly clamp down on the blade.

Posted by Kirk Futrell (Member # 5006) on 12-13-2012, 10:45 AM:

You are correct about it being a black shutter. When I replace the shutter and possibly the hub, will I need to change anything on the software/firmware or should I just be able to follow the shutter timing procedures in the service manual?

Posted by Kirk Futrell (Member # 5006) on 01-08-2013, 11:42 PM:

Steve thanks for your help. As it turns out the customer support at Kinoton was excellent. They sent me two new BLEN chips, (they are up to version 14 now)without charging me, to see if it fixed the problem. It did! Hopefully I won't need the other shutters.

Posted by Manny Knowles (Member # 1171) on 01-09-2013, 11:01 AM:

Wow! That was amazing, Steve. [thumbsup]

Posted by Steve Guttag (Member # 268) on 01-09-2013, 09:11 PM:

Thanks for noticing Manny!