8mm Forum: Urgent Eiki aperture plate problem

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Posted by Adrian Winchester (Member # 248) on October 29, 2005, 08:07 AM:

If anyone can offer some fast advice, I'd be very grateful because I have a problem with a projector needed for a show later today!

I have a B&H 3592/Eiki ENT that was bought brand new last year, so nothing is old or worn. For some reason, the aperture plate has started moving during projection, not constantly, but it seems to slip quite often. I then have to use the framing lever to move it back into the right position.

I'm hoping that it's simply a bit loose and needs tightening, but if this is the case, I'd appreciate advice on what exactly to tighten. I have a service manual but it doesn't seem to mention this problem.

Posted by Jan Bister (Member # 332) on October 29, 2005, 11:34 AM:

Hmm. As a quick fix, you could try one of these:

1. Jam something underneath/above the framing lever to stop it from moving.
2. Reduce film gate pressure by adjusting springs. (May lead to focus problems, however)
3. Lubricate both film and gate before projecting.

And 4. I just had a look at my Eiki SSL-0's film gate and there is a screw at the top, right where the film enters the gate. If you tighten that screw it should prevent the gate from moving.

Good luck!!

Posted by Adrian Winchester (Member # 248) on October 30, 2005, 08:04 AM:

Jan,
Thanks for your suggestions. I had to start the show before I saw your message, but fortunately it was problem-free, except I had to make the two or three adjustments when showing some trailers (adjustments beyond typical frame line adjustments) but all was fine during the feature.
I'm reluctant to do anything that changes the pressure in the gate - as I've had trouble with film unsteadiness through the gat with other Eiki's and the 3592 is one of the few I've had where this is harly ever a problem. Having examined the aperture plate further, I see the moving parts behind it have small springs where they are joined at the top and bottom, so the answer may be to tighten these a little.
It's a strange problem, though, because the aperture plate movement is not slow and gradual - when it happens, it seems to be pulled down quite quickly, and it's hard to imagine a film, even when there's a splice, having the effect of pushing it down.

Posted by Jan Bister (Member # 332) on October 30, 2005, 12:03 PM:

Hmm. If you try to move the plate up and down by hand, how easy or hard is that to do? Is there much resistance at all? (It should be quite hard to do that, if it isn't then it's too loose.)

BTW, I'm glad the show went down without major troubles. [Smile]

Posted by Adrian Winchester (Member # 248) on October 30, 2005, 04:07 PM:

If I place a finger on the top of the plate, I can push it down but I have to apply a reasonable amount of pressure. In fact, I also have an SSL, which has an identical aperture plate and lever mechanism, and this feels the same as the 3592 - so I can't say that the 3592 plate is conspicuously loose.

Posted by John Whittle (Member # 22) on October 31, 2005, 08:45 AM:

quote:
If I place a finger on the top of the plate, I can push it down but I have to apply a reasonable amount of pressure. In fact, I also have an SSL, which has an identical aperture plate and lever mechanism, and this feels the same as the 3592 - so I can't say that the 3592 plate is conspicuously loose.

Sorry I didn't see this over the weekend. Would the 3592 be the projector you were having troubles with before?

The plate is held in place by two 3mm nuts on small springs on blind screws on the back. If you over tighten these you run the chance of pulling the blind screw out from the plate. BUT those should be checked to make sure they are in place and tight. Normally these should be set and then coated with a thread lock or paint so they won't loosen.

The other possibility is if the gate was over lubricated, then the plate may be slipping down (if this is the case the plate moves down and the picture on the screen moves up). Before you disassemble and learn the critical parts to re-align when putting it back together, you should try some spray cleaner (like automotive carborator cleaner). Make sure you give it plenty of time to evaporate.

John

Posted by Adrian Winchester (Member # 248) on November 07, 2005, 05:01 PM:

John - thanks for your reply, which I've just seen.

No, it was an SSL that I had the other (steadiness) problem with - the 3592 was obtained new last year and has been fine in every other respect.

I've checked the 3mm nuts, and they look coated and in the right place.

Thanks for the cleaner idea - I'll give it a try and report back when I can.

Posted by John Whittle (Member # 22) on November 07, 2005, 07:11 PM:

Adrian

One other thing to check is the framing lever itself. The fulcrum is held in place with a small (I think it's a 2.3mm) screw and if loose will provide too much play in the framing lever. It's next to impossible to get to without removing the gate from the projector, so check it for play before you decide to take the gate out.

I wonder if you had a "sticky" print and that's what pushed the plate down and the frame line up on the screen. Properly adjusted, you should have equal movement up and down with the frame line being exposed on top or bottom of the frame. If not (and if the print is made to standard and many aren't) then the cam tank needs adjustment.

John

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