Eumig S810D jittery/losing loop and running too fast

[Jonathan Sanders]

I wonder if anyone can help please with a Eumig S810D I've just bought which has two major problems:

1) On about 7 out of 10 test films I've tried, the image - though initially steady - gradually becomes vertically jittery and eventually loses at least the upper loop with the familiar double-image (rolling) effect. Pressing the threading key does not help, or only for a few seconds, nor does reversing the film (as suggested in the manual). This happens on Standard and Super 8, silent and sound, 18 and 24fps. The films were not damaged and have recently projected steadily on other machines. At least one film has been damaged by the S810D itself (torn perfs) when the loop was lost. A few films have, however, projected without any problem.

2) On 24fps the speed is obviously too fast - judging from the raised audio pitch I'd say around 26 to 30fps. (It may also be too fast on the 18fps setting but it's hard to judge with silent films.)

[In case it's relevant, when I first tried the projector, even after a longish warm-up, it ground to a halt a few minutes into the first film at 24fps (the pre-selected setting when it arrived) but after a further warm-up and an 18fps test, that problem hasn't so far recurred.]

Just to explain where I'm coming from: I was a member of the old forum and I've 50 years' experience of operating various 8mm projectors, including several Eumigs, but my technical know-how is pretty much limited to the sort of basic information and maintenance described in user manuals.

[David Strelitz]

Two things I would check:
1 the top sprocket isn't slipping - there is a very small Allen grub screw on the side of the wheel.
2 that the drive plate is not greasy . With the back off you will see the two plates that the drive goes onto one for forward and one for rewind.

[Jonathan Sanders]

Many thanks, David. I'm sorry to be dense, but on the first point is this tiny Allen grub screw on the removable Standard/Super upper sprockets (there are two ordinary screws on each) or on the black plastic wheel that holds the sprockets? I couldn't find any screw on the latter, either on the facing side or on its rim (by peering through the feeding aperture and rotating the wheel to different positions). Or do I have to view it from the other side by removing the back of the projector? (I haven't done that yet though I realise I'll need to for your second point.)

This upper wheel does feel slightly loose - holding the spindle I can turn it back and forth 1-2mm. Is that normal or an indication of the fault you mention? Also, the Super 8 upper sprocket itself (held between my fingers) has a similar degree of looseness, though the Standard one doesn't.

I did find a thread on the archived forum that seems to relate to the same issue on another model but I can't see the referenced crack in the plastic from the front (if that's the right place to look?)
8mm Forum: Eumig 807D Question (film-tech.com)

[Brian Fretwell]

I can't think of the reason for it running fast. If you were on 60hz mains I would suggest the setting for that was wrong, but if it were wrong on 50Hz it would run slow.

Of course you can slow it down by moving the speed adjust to somewhere between 24 and 18 fps (motor running but control lever in stop position) the benefit of not having just a switch for 18 or 24 fps.

[Jonathan Sanders]

Thanks, Brian. I didn't realise that, even in stop position, the speed could be set somewhere between 18 and 24fps (the manual implies one or the other). Besides correcting the audio pitch on sound films, that would be useful for many silent films which are too slow at 18 but too fast at 24fps.

[David Strelitz]

I can't think of the reason for it running fast. If you were on 60hz mains I would suggest the setting for that was wrong, but if it were wrong on 50Hz it would run slow.

Of course you can slow it down by moving the speed adjust to somewhere between 24 and 18 fps (motor running but control lever in stop position) the benefit of not having just a switch for 18 or 24 fps.

On 60hz you can get the 18 down to 16.. JS whip the back off, and you will will see that in the 18 position on the front, if you move the 50/60hz switch then the 18 position can be lowered. Clean the drive plates and drive bush while you are there.
1-2mm play seems ok. Rotating the wheel at the back will allow you to access the grub screw via an access hole at right angles to the top sprocket mount.
Worth also checking the rear sprocket mount for play.

[Jonathan Sanders]

Thanks again, David. Anyone... what's the best/safest way of cleaning drive plates? I have isopropanol and cotton buds - would that do for a start?

[Brian Fretwell]

That is the most frequently mentioned method of cleaning them mentioned here. I would recommend it.

[David Strelitz]

Thanks again, David. Anyone... what's the best/safest way of cleaning drive plates? I have isopropanol and cotton buds - would that do for a start?

I save my isopropyl for video heads. Meths will do. Cotton bud on the brass drive but on the plates, a bit of rag or even a foam backed kitchen scourer, like you might use on a nonstick pan. You're just wanting to remove any grease embedded on the plates. Hopefully the brass drive is making good contact with the drive plate when it is in the selected position. If it's not that's a whole different ballgame.

[Jonathan Sanders]

Thanks to both. The drive plates do not seem greasy but I'll give them a wipe as suggested. They have superficial concentric wear marks, reflecting the two main speed settings, but I assume that's normal.

Rotating the wheel at the back will allow you to access the grub screw via an access hole at right angles to the top sprocket mount.

I'm still struggling to locate the tiny grub screw. How do I turn the wheel from the back? Viewing from the rear, there's a white plastic cog - one of four - that seems to propel the black upper wheel at the front but even the cog cannot be turned by hand more than a few mms (I have the power disconnected for safety while the back is open). There are two tiny holes in this white cog - is one of these the access hole?

By the way, this cog is much greasier than the other three. There are lines in the grease that at first looked like a crack but I don't think so. It's all reaching the limits of my eyesight even with glasses and a magnifier!

[David Strelitz]

See Pics. Access hole is where film is threaded above the Lens (removed in Pic) Rear Knob in other pic. If the plates are physically grooved that is not good. If superficial just clean if not you could try emery cloth to re-surface. Power on - run - hold emery cloth against the plates but be careful as there are Live terminals.
Alternatively look for a new projector. 😥

[Jonathan Sanders]

Many thanks, David - a picture is worth a thousand words and it's very kind of you to upload them. My confusion was that the "access hole" is what I call the "feeding aperture" and I only know "the wheel at the back" as the "inching knob" (I'm autistic so tend to have fixed names for everything).

However, I'd looked through this feeding aperture/access hole before (previously using the motor to rotate the wheel) and, after turning it 360 degrees several times with the inching knob, I'm afraid I still don't see any grub screw on "the side of the wheel" (if "side" equals rim or edge). All I see are two indentations/sockets for the Standard and Super sprockets. I'll ask someone else to examine it, in case my eyesight is worse than I thought. I'm also looking on the archived forum and YouTube for any photos or videos that might pinpoint the screw.

The drive plates are not physically grooved (I can't feel the wear marks). Cosmetically, the projector is in excellent condition and appears generally to have had little usage - though maybe that's the cause of the problem!

[David Strelitz]

Yes my original description of "access hole" could have been clearer. 🙄
Another pic shows grub screw.
If you don't resolve and if you think the projector is in good condition and worth getting serviced, then John White is the man. Shame you are so far North of Watford 😁 but securely packed, it is still worth sorting. http://www.the8mmshedshop.co.uk/

[Jonathan Sanders]

Thanks again, David. I was expecting a much smaller screw. Now I'm sure I'm looking in the right place, I believe I can confidently state the upper sprocket wheel on my S810D has no such screw or screwhole. I'd be curious to know if anyone else has the same model without it?

Thanks for the servicing suggestion too. I might look into it if cleaning the drive plates doesn't help.

[Brian Fretwell]

I've just checked my S 810D and 710D, neither have this, perhaps it was on later manufactured ones only.