Revere Model 48 not maintaining bottom loop

[Aaron White]

I purchased a Revere Model 48 Projector the other day that appeared to be in working order, but upon getting it home, I discovered that the projector would not maintain the bottom loop of film between the film pressure plate and the bottom sprocket. I have been troubleshooting for a while but cannot seem to find what is wrong.

As soon as the clutch is engaged, the film momentarily doesn't move through the film plate area as the bottom sprocket pulls the bottom loop into a straight line. As a result of the film not moving through the film plate area, the top loop becomes about an inch higher once the sprocket starts rotating. Once the loop on the bottom becomes a straight line, the film begins to move through the film plate, and the top loop remains at the increased height. Because the bottom loop is gone, the bottom sprocket pulls the entire reel of film in front of the light at the same rate instead of frame by frame, creating an unclear picture.

My first thought was that the bottom sprocket was moving faster than the top one, but I don't think that would explain the film momentarily not moving through the plate area at all once the sprockets start rotating. Could there be an issue with the film plate mechanism itself? I am totally clueless and would appreciate any help.

Here are some pictures of what the film looks like seconds after the clutch is engaged. The loops both started at roughly 1.5 inches in height:

[Maurice Leakey]

Aaron
If the top loop get bigger, and the lower loop disappears, then it would seem that the film is not advancing correctly through the gate.
Perhaps there is a problem with the claw which may be damaged, or even broken off.

[John Burgess]

Hi Aaron, recently had this problem on my Fujica sound 8. After much head scratching and investigating it turned out to be the claws not retracting properly within the gate. I am not familiar with your projector but if you can open the gate with film in situ then turn the inching knob , put your forefinger onto the film over the claw, you should then feel the claw doing its job ,moving one frame at a time them retracting. If this is not happening the claw will need adjustment. You would ideally need a workshop manual to carry out this task. Hope this helps, and good luck!
John

[Aaron White]

Thanks for the reply Maurice. I attempted to remove the plate covering the claw mechanism to inspect it but was only able to get it partially off. It looked ok from what I could see but there could be something broken farther in that I can't get to. I put the plate back on and took a slo-mo video of the claw in action. It seems to function properly but I'm no expert. Perhaps it's not coming out far enough? Again any help would be appreciated.

Here's the link to the video: https://www.youtube.com/watch?v=VtqGIz6oTqg

[Maurice Leakey]

Aaron
Having now watched your short video. The claw does seem to be working.
However, there is a load knocking noise and I wonder if the claw is hitting the side of its aperture slot and not actually engaging with the film.
I have watched a video of the Revere 48 on YouTube. Whilst the motor does seem noisy it appears to run with no extraneous noise.

Revere model 48 16 mm projector - YouTube

[Nantawat Kittiwarakul]

Try manually advancing the film by using the inching knob (just right behind the lens). Does the claw properly engaging the sprocket holes?

[Aaron White]

John, Maurice, and Nantawat thank you all for your help.

I wasn't able to fit my finger behind the film pressure plate but was able to push lightly on the film with an implement while I turned the inching knob. The claw does not engage the sprocket holes, and upon further inspection, I noticed that the claw was hitting the aperture slot, as Maurice suspected. Just before the claw comes out of the slot, it hits the top right corner of the aperture and then moves downward at a very slight angle, just missing the sprocket holes. It would appear that the claw needs to be adjusted, as John said.

I am hesitant to remove the panel covering the claw mechanism because doing so would require me to remove some rivets that I'm not sure I could replace. I have looked online for a workshop manual that would walk me through the adjustment process but haven't had any luck in finding one. If anyone has experience repairing the Revere Model 48 and could give me some guidance, please let me know.

[Maurice Leakey]

...Upon further inspection, I noticed that the claw was hitting the aperture slot, as Maurice suspected...

Aaron
Can you perhaps adjust the rear aperture plate to clear the hitting claw?

[Aaron White]

Maurice,
I did attempt this, but when I adjusted the rear aperture plate so that the claw didn't hit it, the film pressure plate no longer fit into place properly. Also, once adjusted, the screw holes on the aperture plate didn't line up, so I couldn't secure it in place.

[Maurice Leakey]

Aaron
How disappointing.
It does now seem that you have exhausted the possibilities.
It is indeed a problem that many older projectors were never designed for much future maintenance.

[Aaron White]

Yes, it is a shame. I will wait a while longer to see if anyone else has any ideas. If not, I will remove the roll pins and rivets necessary to get to the claw mechanism, probably by drilling since they are only accessible from one side, and hope that I'm able to replace them. I don't know if I'll be able to repair the mechanism, but I figure it's worth a shot.

[Maurice Leakey]

...I will wait a while longer to see if anyone else has any ideas. I don't know if I'll be able to repair the mechanism, but I figure it's worth a shot...

Aaron
If you do proceed I wish you the best of luck.