8mm Forum: Eumig 824 Volume Fluctuates Up & Down

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Posted by Janice Glesser (Member # 2758) on May 11, 2017, 07:08 PM:

I just received a Eumig 824 projector. How many times have you heard..."It's in perfect condition....EXCEPT FOR ONE THING...." Well I'm also singing that tune right now.

Before I even opened the back I knew there was a problem. First I had to turn the volume knob all the way to the max to hear anything. Then the audio volume like a wave would abruptly dip and then rise again. This behavior is continuous.

The next thing I noticed after opening the back was this little clue:

I know very little about this model and hope I can get some ideas on how to troubleshoot.

Any help appreciated [Smile]

Posted by Paul Adsett (Member # 25) on May 11, 2017, 07:40 PM:

Janice, try turning the machine on, in standby mode, then press the red recording button and hold it in place, and turn the control knob to the forward with sound (4-o'clock) position. This activates the sound recording circuitry. Do this a few times and see if it solves the low sound problem, which on these machines is often associated with corroded or dirty contacts on the recording switch. You may also wish to try removing the speaker lid and blowing compressed air around these contacts which are on a sliding switch at the end of the recording switch actuation cable.

Posted by Janice Glesser (Member # 2758) on May 13, 2017, 02:40 PM:

Thank you Paul...That helped slightly...but to hear any sound the knob has to be at least at the half-way mark and of course as I turn it further there is significant hummm.

As far as the sound cutting out...It turns out that is only occurring with one reel of film. I tried other reels both R8 & S8 on the Eumig 824 and there was no drop-out ...so it appears to be just that one reel. Comparing the films sound stripe I couldn't see what was different...so it's a mystery to me. I ran the same reel thru my Eumig 810D and the sound was fine....no drop-out. I'm guessing there may be something with the 824 sound head.

I have the user manual which contains a schematic, but unfortunately I can't read schematics [Frown]

I read all the Forum back threads on this projector...but most just addressed the "no sound" issue.

I'm not sure if this is a sound head or component issue. I connected a small external speaker...but the volume was still low. So I'm guessing the built-in speaker is ok. I don't like that you can't test the audio without putting the back cover back on...Grrrgh! Maybe I can rig up some alligator clips.

Anybody ever worked on one of these? I don't really know where to start trouble-shooting.

[ May 13, 2017, 03:46 PM: Message edited by: Janice Glesser ]

Posted by Will Trenfield (Member # 5321) on May 13, 2017, 06:34 PM:

Odd. I wonder if the reel you mention has shrunk given that other films play ok. Perhaps your 810 is more tolerant than your 824? I've a L & H sound film that played up but was fine after treating it with Filmguard.

Posted by Janice Glesser (Member # 2758) on May 13, 2017, 09:33 PM:

Yes Will... very strange. I think I'll get some Filmguard and see if that has any effect....can't hurt.

Posted by Paul Browning (Member # 2715) on May 14, 2017, 06:27 AM:

Hello Janice, perhaps the film and head are not in continuous contact with each other, giving you this up and down effect. Do these have a spring loaded presser's, I would check this if you can locate it, may have to remove the front cover, perhaps lost or sticking or a broken spring preventing even pressure on the sound head.

Posted by Tom Photiou (Member # 130) on May 14, 2017, 06:40 AM:

Janice, once that machine is all up and running you will be very pleased with it. Those eumigs are extremly kind to film and are very quite with excellent sound and light. And they look very good. I dont think there look has ever dated over the years.

Posted by David Skillern (Member # 607) on May 14, 2017, 07:15 AM:

Hi Janice,

I hope you get this problem sorted - as i've got 2 of these machines and they both perform very well.

Posted by Janice Glesser (Member # 2758) on May 15, 2017, 06:02 PM:

In running some more sound film through the projector...some films are louder than others...but I still think there's a sound issue effecting the volume and there's a high-pitched screeching sound that comes and goes on longer reels. I'm still baffled at the one reel where the audio drops out.

I'm guessing that these are not common problems. However...perhaps one of you has knowledge of the sound heads? How to get to them? What to look for? They appear to be in a metal casing...so I can't really see the heads by just removing the cover. There doesn't seem to be a service manual on this projector.

Posted by Paul Adsett (Member # 25) on May 15, 2017, 08:11 PM:

Janice, this may help you:

http://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=000254

Posted by Janice Glesser (Member # 2758) on May 15, 2017, 09:19 PM:

Thanks Paul...Just as you posted I found those instructions online from a 2013 presentation that Dino Everett was involved. This is just what I was looking for [Smile]

Small Gauge Projection and the Art of Projector Maintenance and Repair
November 5‐6, 2013
Association of Moving Image Archivists Annual Conference
Richmond, VA

Posted by Janice Glesser (Member # 2758) on May 17, 2017, 01:05 PM:

Steps 1-3. Following the instructions above I removed the main control knob (1)...the volume knob (2)... and the mixing control knob (3). I unscrewed the screw between the volume and mixing knobs (4). I'm not sure why it's referred to as the "side" panel. I call it the "front" panel...am I missing something? [Confused]

... but the panel loosens on the right side, but not the left. Something still seems attached...could it be the lamp brightness selector switch?

Step 4. Not sure what "unplug the sound head" means. I see the 2 white wires going from the sound assembly to the switch...but nothing that looks like it can be unplugged.
[Confused]

Is this the single screw holding the head assembly to the chassis?

Steps 5&6. Even though I haven't even gotten to the removing the sound head stage...are these the 6 screws the instructions are referring to? Are the 2 outer screws the ones I've numbered 1 and 5?

Am I safe in assuming that the instructions are more for earlier Eumig 800 series models and not for the 824?

Posted by Dominique De Bast (Member # 3798) on May 17, 2017, 01:59 PM:

Janice, I have the same projector but not working correctly (and since the 8 mm gate is missing I didn't want to spend too much effort on it so it's still not working). I could however remove the part you mention but it was not easy so I thought there was glue but it not that : there is a metallic piece that holds that part so you have to slide a little bit to be able to remove it. Be careful as the lamp power selector is connected with three wires.

Posted by Janice Glesser (Member # 2758) on May 17, 2017, 02:31 PM:

Thanks Dominique...I'll give it another try and let you know. Sometimes the hardest part is just getting to the area that needs fixing [Roll Eyes]

Posted by Paul Adsett (Member # 25) on May 17, 2017, 06:47 PM:

Hi Janice,
As Dominique has pointed out, there is a little clip at the back end of the chassis that engages with the back end (furthest from lens end) of that little side cover. So you have to move the side cover about a half inch towards the lens to totally remove the side cover. You may also need to pull the wires off the HI/LOW lamp switch as well (this switch is unique to the 824).
Yes that big screw holds the head assembly to the chassis wall. Make sure you have no power to the projector and have rotated the control knob to the 4 o'clock position before removing (or replacing) the sound head. On the 802 and 820 the head has a small harness and plug which plaugs into a small socket on the chassis. The 824 head may be hard wired, so proceed carefully.
On the sound head, DO NOT TOUCH screws 2,3,4,6,these are the elevation and azimuth adjustments for the head. You only need to remove screws 1 and 5 that hold the mumetal shield in place.

Posted by Janice Glesser (Member # 2758) on May 19, 2017, 03:01 PM:

Thanks for the details Paul. I haven't had a chance to get back to the head cleaning yet...but I should at least be able to get the panel off this time [Smile]

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