8mm Forum: Eumig S807 Reverse Projection Loud Clatter

This is topic Eumig S807 Reverse Projection Loud Clatter in forum 8mm Forum at 8mm Forum.

To visit this topic, use this URL:
https://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=011913

Posted by Martin Dew (Member # 5748) on November 28, 2017, 11:34 AM:

My Eumig S807 has just started making a clattering noise on reverse 24fps and 18fps projection, forward seems to be fine. (Plus the pull-down claws are in good order.)

It appears that the top loop is being lost on reverse projection after a couple of seconds, and the film is travelling 'flat' from the gate to the ridge of the top sprocket.

I have looked up similar Eumig 800 series items here on the forum, but this particular issue doesn't seem to be addressed.

Many thanks in advance if any of you can help.

Posted by Paul Adsett (Member # 25) on November 28, 2017, 12:39 PM:

Martin, check that the top feed sprocket is not slipping on the axle. This is a common problem with Eumig 800's, caused by the top plastic sprocket holder developing a crack caused by the stress from the little grub screw. Maybe the grub screw just needs tightening, or if the plastic sprocket holder is cracked you can fix it with epoxy.
I have had to fix two of my Eumig 800's for cracked top sprocket holder, and ended up epoxying the black plastic sprocket holder directly to the shaft.

Posted by Martin Dew (Member # 5748) on November 28, 2017, 01:04 PM:

Thanks, Paul. Is there any chance you or anyone here has a service manual pic of the assembly? I don't know how the top sprocket and loop former assembly comes apart to locate the grub screw.

Posted by Paul Adsett (Member # 25) on November 28, 2017, 01:43 PM:

You don't need to disassemble anything. The grub screw can be reached by a small hex socket driver inserted through the front of the loop former (in the direction you feed the film in). Use the inching knob to get the screw around to the front.

Posted by Martin Dew (Member # 5748) on November 28, 2017, 05:00 PM:

Thanks, Paul. Got it.

Posted by frank arnstein (Member # 330) on November 29, 2017, 01:31 AM:

Hi Martin and Paul,

As this is only happening in reverse project mode, I think it's unlikely to be a loose top sprocket slipping on the shaft. That would make the top loop get bigger as it slipped in reverse, not smaller and then disappear.

I suspect it may have an overtight reverse friction clutch which drives the front arm spindle. Sounds like it is set too tightly and is pulling the film off the top sprocket when in reverse project.

Try loosening the clutch spring setting to where it gently rewinds the film without pulling back hard and ensure that the reverse clutch slips continuously the whole time it's reverse projecting.

That should stop the film being yanked off the top sprocket in reverse, causing top loop loss.

Let us all know how you go with it Martin.

dogtor frankarnstein

[Smile]

Posted by Martin Dew (Member # 5748) on November 29, 2017, 07:52 AM:

Thanks, Frank.

Here's the good forward loop:

Here's the bad reverse loop:

This is what I see on the top sprocket via the feed:

I don't think the reverse spindle is the problem, Frank, because the symptom occurs just using loose leader without spool. Presumably you're suggesting that tension from the rewind spindle is the cause?

I'm not sure I know how to make the adjustment to the top sprocket, Paul. Is this configuration the same as the other 800 series PJs? All I can see is the stainless steel barrel embedded in the sprocket wheel.

Posted by Paul Adsett (Member # 25) on November 29, 2017, 08:19 AM:

I have to respectfully disagree with Frank on this one. A slipping top sprocket may not be a problem in forward projection when the torque on the sprocket from the feed spool is very low.But in reverse mode the torque induced on the sprocket by the rewind film tension is much higher and slippage would result in a flattening of the top loop.
Martin, push down on the plastic tab and see if you can rotate the sprocket by hand. If you can, then that is your problem and you will have to repair or bond the innermost plastic piece to the shaft. To do this you first pull the sprocket off the shaft(push down on the black tab below the sprocket, grab the serrated plastic edge on the knob and pull out. Now locate the little grub screw on the innermost piece that is still bolted to the shaft. Loosen the grub screw and pull that innermost piece off the shaft. Look for cracks around the grub screw (I will almost guarantee they are there).

Posted by Martin Dew (Member # 5748) on November 29, 2017, 02:31 PM:

I've discovered that the bottom loop is getting lost on reverse too, even though the chatter seemed to be coming from the front end. So I figured there must be some drag elsewhere, and worked backwards. I removed and reattached the magnetic shield to the sound heads (which I've done before to clean the heads) and that didn't solve it. Then I realised that the rear sprocket was tugging on the film as it traveled backwards into the machine.

I think the rear sprocket guard is somehow dragging on the rear sprocket itself, causing it to tug on the film. If I move the guard slightly lower, the tugging stops, and the loops are preserved. I still don't understand this because keeping the guard in its most upright position has never presented a problem before, and it doesn't appear that anything is blocking anything else.

I now get the feeling something more complex is going on here.

Posted by Paul Adsett (Member # 25) on December 02, 2017, 03:06 PM:

Hi Martin,
Are you having any success sorting your Eumig 807 problem?

Posted by Martin Dew (Member # 5748) on December 03, 2017, 04:39 PM:

No, not yet, Paul. Kevin suggested I check the the rear sprocket drive gear for cracks, which I did today, but that looks absolutely fine and tight too. It's all a bit odd.

Posted by Martin Dew (Member # 5748) on February 27, 2018, 07:30 AM:

Paul, I finally got this sorted by John White. The metal plate which is attached by a screw to the rear sprocket guard had come slightly out of alignment, causing the loops to be lost at the front end of the projector during reverse projection. He repositioned the plate and marked the new screw position with red paint.

Posted by Paul Adsett (Member # 25) on February 27, 2018, 11:04 AM:

Well, that's good news Martin. Very glad your projector is back in service! [Smile]

UBB.classic^TM 6.3.1.2